Question 1 1.25 / -0
The number of non-negative real roots of 2x - x - 1 = 0 is
Solution
2x - x - 1 = 0x = x + 1o = 1 and x + 1 = 0 + 1 = 11 = 2 and 1 + 1 = 2
Question 2 1.25 / -0
The sides of a triangle ABC are positive integers. The smallest side has length 1. Which of the following statements is true?
Solution
1 + b > c ⇒ c - b < 1 and 1 + c > b ⇒ b - c < 1, then -1 < b - c < 1
Since b, c are integers: so b - c = 0 ⇒ b = c
Semiperimeter of triangle =
Area of the triangle =
This is irrational.
Question 3 1.25 / -0
The real numbers 'x' satisfying
> 1 are precisely those which satisfy
Solution
≥ 0
∴ x - 1 ≥ 0, x < 1 ...(i)
> 1 - x
x + 5 > 1 + x
2 - 2x
x
2 - 3x - 4 < 0
(x - 4) (x + 1) < 0
x ∈ (-1, 4) ...(ii)
From equations (i) and (ii), x lies between (-1, 1).
Question 4 1.25 / -0
Two trains start at the same time from station A and station B and proceed towards each other at the speeds of 16 km/hr and 21 km/hr, respectively. When they meet, it is found that one train has travelled 60 km more than the other. What is the distance between the two stations?
Solution
Suppose speeds of trains be S
1 and S
2 after starting from stations A and B, respectively.
Then, distance between the two stations =
= 60
km = 60 ×
km = 444 km
Question 5 1.25 / -0
If a3 + b3 + c3 = 3abc, then a + b is equal to
Solution
a
3 + b
3 + c
3 - 3abc = (a + b + c)(a
2 + b
2 + c
2 - ab - bc - ca)
If a
3 + b
3 + c
3 = 3abc, then either a + b + c = 0 or (a
2 + b
2 + c
2 - ab - bc - ca) = 0
If a + b + c = 0, then a + b = -c
Now, if (a
2 + b
2 + c
2 - ab - bc - ca) = 0, then
(2a
2 + 2b
2 + 2c
2 - 2ab - 2bc - 2ca) = 0
Or, (1/2)((a - b)
2 + (b - c)
2 + (c - a)
2 ) = 0, which is only possible if a = b = c
As in the answer options, we only have a + b = -c, so it is correct.
Hence, answer option (3) is correct.
Question 6 1.25 / -0
In the figure given below, angle RQM = angle PSR. Further, it is also known that PS = 5 cm, SR = 5 cm, RQ = 6 cm and PQ = 4 cm. What is the approximate area of quadrilateral PQRS (in cm
2 )?
Solution
∠RQM + ∠RQP = 180°
and ∠PSR + ∠PQR = 180°
Hence, PQRS is a cyclic quadrilateral.
And by Heron's formula, we can find the area of the cyclic quadrilateral.
25 cm
2 .
Question 7 1.25 / -0
What will be the volume of frustum in the given figure?
Solution
Volume of frustum =
-
=
× 3.14 × 5
2 × 10 -
× 3.14 × 3
2 × 4
= 513.3 m
3
Question 8 1.25 / -0
A cube has a volume of 128 cm3 . It is divided into 8 equal cubes. Then, the ratio of an edge of a smaller cube to an edge of the original cube is
Solution
n × V
c = nx(side)
3 = 128
8 × V
c = 128
Thus V
c =
= 16 cm
3 = 2
3 × 2 cm
3 = a
3 , where a is a side of the small cube.
A
3 = 2 × 2
3 × 2
2 = 128, where A is a side of the large cube.
Now
Question 9 1.25 / -0
What is the difference between the volume of a cone with r = 4 cm, h = 4 cm and the volume of a cone with r = 2 cm and h = 2 cm?
Solution
Volume =
-
=
× 3.14 × 4
2 × 4 -
× 3.14 × 2
2 × 2
= 58.6 m
3
Question 10 1.25 / -0
If the volume of a sphere increases by 72.8%, then its surface area increases by
Solution
Suppose initial radius of the sphere = r
So, volume of the sphere =
and surface area of the sphere =
After increment in volume, volume of the sphere =
So, the required increase in sphere = 1.2 r
Increase in surface area of sphere =
Hence, percentage increase in surface area =
= 44%
Question 11 1.25 / -0
A and B can complete a piece of work in 20 and 30 days, respectively. A and B started the work and after 10 days, A left the job and then C joined B and completed the job by taking 1 day more than the estimated time. How many days would C take to complete the work independently?
Solution
A and B can do
and
of the work in 1 day.
Assume that 'C' takes 'd' days to complete the work alone.
Estimated time when only A and B finish the work =
= 12 days
But 'C' replaced 'A' after 10 days and so it takes 13 days.
So,
= 1
⇒ d = 45
C would take 45 days to complete the work independently.
Question 12 1.25 / -0
If one root of the equation ax2 + bx + c = 0 is twice the other, then
Solution
Let one of the roots be P, so the other will be 2P.
Sum of the roots = P + 2P = 3P =
P =
And product of roots P × 2P = 2P
2 =
2
2 ×
So, 2b
2 = 9ac
Question 13 1.25 / -0
If 2 + i
is a root of the quadratic equation x
2 + ax + b = 0, where a, b ∈ R, then the values of a and b are respectively.
Solution
If the 1
st root is R
1 = 2 + i
, the other root has to be R
2 = 2 - i
R
1 + R
2 = 4 = -a;
a = -4
R
1 R
2 = 7 = b
∴ b = 7;
Hence, a = -4, b = 7
Thus, answer option (3) is correct.
Question 14 1.25 / -0
Let S
n be the sum of all integers 'k' such that 2
n < k < 20
n + 1 , for n
1. Then, 9 divides S
n if and only if
Solution
Suppose n is odd.
Then, for n = 1, k is between 2 and 400.
Then, sum S
1 =
(3 + 399) = 200 × 397,
which is not divisible by 9
So, n is also not of the form 3k + 1 and 3k + 2.
So, n is an even number.
Question 15 1.25 / -0
The inequality |z - 2| < |z - 4| represents the half plane
Solution
Consider the Argand plane. For any point Z
1 on the line x = 3, we have
|Z
1 - 4| = |Z
1 - 2|
For any point Z
2 to the left of x = 3, we have |Z
2 - 2| < |Z
2 - 4| as the distance Z
2 A < Z
2 B
For any point Z
3 to the right of x = 3, we have Z
3 B < Z
3 A.
Thus, the half plane x < 3 is represented by |Z - 2| < |Z - 4|.
Question 16 1.25 / -0
Two charges of the same magnitude move in two circles of radii R
1 = R and R
2 = 2R in a region of constant uniform magnetic field
. The works W
1 and W
2 done by the magnetic field in the two cases, respectively, are such that
Solution
W
1 = W
2 = 0
As we know, work W =
In a magnetic field,
So, force is always perpendicular to velocity.
So, the dot product will be zero.
From above, work will always be zero.
Question 17 1.25 / -0
Two projectiles are fired from the same point with the same speed at angles of projection of 60° and 30°. Which one of the following is true?
Solution
Range of the projectile is the same if the angle of projection with horizontal is either θ or (90° - θ). Here, angles of projection are 30° and 60° (= 90° - 30°), so the range of two projectiles will be the same.
Question 18 1.25 / -0
Two blocks of the same volume with densities
1 and
2 , such that
1 >
2 >
w , are immersed in water (density =
w ). If the buoyant force experienced by m
1 is F
1 and that by m
2 is F
2 , then
Solution
If the volume of two blocks is the same, then the buoyant force acting on the two blocks will be the same irrespective of their densities. So, the buoyant force required to overcome the gravitational force will be equal, i.e. F1 = F2 . Option (3) is correct.
Question 19 1.25 / -0
Directions: A body is moving in a circle as shown in the figure starting from point A clock–wise.
It completes one cycle in 20 s.
What will be the average velocity as it starts from A and reaches C after completing two cycles (take the line joining the origin and C as south and the origin and A as west)?
Solution
Time taken in 2 cycles = 20 + 20 = 40 sec
Time taken to cover distance from A to C in a clockwise direction
=
of time taken to complete 1 cycle
=
= 15 sec
Total time = 40 + 15 = 55 sec
Displacement = AC =
=
m
Average velocity =
=
m/s
Displacement vector is in South East direction.
Hence, option (2) is correct.
Question 20 1.25 / -0
The projectile attains maximum height when the projection angle is
Solution
Maximum height attained by the projectile is given by:
Height will be maximum when
Question 21 1.25 / -0
A torch welder is working without his safety glasses. Which of the following parts of his eyes is most likely to get affected?
Solution
If a torch welder is working without his safety glasses, his retina is most likely to get affected.
Question 22 1.25 / -0
Which one of the following graphs correctly represents the distance-time variation for a body released vertically downward from the top of a building?
Solution
Using
, for the object at rest u = 0,
Hence option 1 is correct.
Question 23 1.25 / -0
A vessel consists of two plane mirrors at a right angle (as shown in figure). The vessel is filled with water. The total deviation in the incident ray is
Solution
As the light is incident normaly on the air - water interface,
hence, there will be no refraction at the interface,
If a ray of light strikes the mirror at an angle of 45°, it will deviate by 90° and further strike the second mirror at an angle of 45° and again deviate by 90°.
After reflection it will strike the water - air interface normally and pass without any refraction.
Total deviation produced is 180°.
Question 24 1.25 / -0
The temperature of a metal coin is increased by 100°C and its diameter increases by 0.15%. Its area increases by nearly
Question 25 1.25 / -0
A solid cube and a solid sphere of identical material and equal masses are heated to the same temperature and left to cool in the same surroundings. Then
Solution
If mass and density are equal, then volume will also be equal.
Now, surface area of a cube = 6a
2 surface area of a sphere = 4
r
2 On comparing, area of a cube is greater than the area of a sphere.
More the surface area, faster will the object cool down.
Question 26 1.25 / -0
A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10 V. The potential at a distance of 2 cm from the centre of the sphere is
Solution
If we take any charge from one point to another inside a charged spherical shell then no work will be done, this means that inside a spherical charge the potential at all points is the same and its value is equal to that on the surface, that is 10 V in this case.
Question 27 1.25 / -0
A total of 4,900 J. was expended in lifting a mass of 50 kg. The mass was raised to a height of (g = 10 m/s2 )
Solution
w = 4900 J; M = 50 kg; h = ?
4900 = 50 × 10 × h
h =
= 9.8 m
Question 28 1.25 / -0
A planet of mass m is moving around a star of mass M and radius R in a circular orbit of radius r. The star abruptly shrinks to half its radius without any loss of mass. What change will be there in the orbit of the planet?
Solution
Since there is no mass change and also no change in the distance between centres of both, the radius would be unchanged.
Question 29 1.25 / -0
The Earth moves in an elliptical orbit with the sun S at one of foci as shown in the figure. Its rotational kinetic energy is maximum at the point
Solution
Key Idea: In planetary motion, angular momentum remains conserved.
The earth revolves around the sun once in a year. In order to find the rotational kinetic energy about the sun, we may treat the earth as a point mass, of moment of inertia I. If
is angular velocity of earth, then
K
rot =
I
2 In planetary motion, angular momentum remains conserved. At A, the moment of inertia is least, so angular speed is maximum. So, at A, rotational kinetic energy is maximum.
Question 30 1.25 / -0
Figure (a) below shows a Wheatstone bridge in which P, Q, R and S are fixed resistances, G is a galvanometer and B is a battery. For this particular case, the galvanometer shows zero deflection. Now, only the positions of B and G are interchanged, as shown in figure (b). The new deflection of the galvanometer
Solution
In the figure (a), Ig = 0g will be zero.
Question 31 1.25 / -0
The IUPAC name of acetaldehyde (CH3 CHO) is ________.
Solution
The IUPAC name of acetaldehyde (CH3 CHO) is ethanal.
Question 32 1.25 / -0
Which of the following can behave both as an acid and a base according to both the Arrhenius and the Bronsted concept?
Solution
Water is an amphoteric substance and can behave as an acid as well as a base according to both the Arrhenius and the Bronsted concept.
Arrhenius Concept: Since it furnishes both H
+ and OH
- ions in the aqueous solution.
Bronsted Concept: Since it can accept as well as donate a proton.
Water can behave as an acid as well as base.
Ammonia is a Bronsted acid and a Lewis as well as a Bronsted base.
Question 33 1.25 / -0
Which of the following does not have an sp2 hybridised carbon?
Question 34 1.25 / -0
Which of the following elements has the greatest tendency to lose electrons?
Solution
The tendency to lose electrons increases as we go down a group because the atomic radius increases and the ionisation energy decreases. So, in the case of alkali metals, Fr has the highest tendency to lose electrons.
Question 35 1.25 / -0
One mole of nitrogen gas, on reaction with 3.01
10
23 molecules of hydrogen gas, produces
Solution
The chemical reaction for the preparation of ammonia is:
N
2 + 3H
2 2NH
3 It is clear from the above equation that 3 moles of hydrogen combine with 1 mole of N
2 to give 2 moles of NH
3 .
(1/2) moles of hydrogen combines with 1/6 moles of N
2 to give
moles of NH
3 .
Therefore, number of molecules of NH
3 formed =
× 6.02 × 10
23 = 2.0 × 10
23 molecules
Question 36 1.25 / -0
Which of the following compounds has the highest value of dipole moment?
Solution
In H-F, fluorine has very high electronegaivity, while hydrogen is very low, therefore there is large charge separation and so the dipole moment increases, however, H-Cl has more dipole moment than H-F, bcoz the H-F bond length is very small as compared to H-Cl, while the difference in charge is not much.
Question 37 1.25 / -0
How many atoms are present in 12
10
23 g of C?
Solution
1 g of carbon =
atoms of C
12
10
23 g of carbon =
atoms of C
= 6.022
10
23 10
23 atoms of C
= 6.022
10
46 atoms of C
Question 38 1.25 / -0
Compressibility of gas is less than unity at S.T.P, therefore
Solution
The compressibility factor (Z) =
= 1
(for ideal gas)
(Z) =
< 1 (real gases)
∴
> 1 or V
m < 22.4
Question 39 1.25 / -0
The aqueous solution of which of the following compounds neutralises an aqueous solution of caustic soda?
Solution
Neutralisation involves the reaction of an acid with a base resulting in the formation of corresponding salts and water. Since caustic soda (NaOH) is a base, it can be neutralised only by an acid. CH
3 COOH, being an acid (as it releases H
+ ions in an aqueous solution), can neutralise NaOH.
The reaction takes place as follows:
On the other hand, KOH and NH
4 OH are bases (as they release OH
– ions in an aqueous solution) and cannot neutralise NaOH. NaCl, being a neutral salt, cannot neutralise caustic soda.
Question 40 1.25 / -0
The EMF of the cell is related to the equilibrium constant of the cell reactions as
Solution
The EMF of the cell is related to the equilibrium constant of the cell reactions as
In K
c =
Question 41 1.25 / -0
In bleaching powder (CaOCl2 ), the oxidation number of two chlorine atoms is
Solution
In bleaching powder (CaOCl
2 ), the oxidation number of two chlorine atoms is − 1 and + 1.
Question 42 1.25 / -0
Which of the following is the correct decreasing order of reactivity of the elements?
Solution
The reactivity series of metals is the arrangement of metals in decreasing order of their reactivity. The series is as follows:
Question 43 1.25 / -0
What are the main products of the oxidation of alkene with ozone?
Solution
In the reductive cleavage, the ozonides are treated with a reducing agent such as Zn dust and water to form aldehydes or ketones or a mixture of both depending upon the structure of the alkene.
Question 44 1.25 / -0
Which of the following reactions is not possible?
Solution
In general, a more reactive metal can displace a less reactive metal from its salt solution. The reactivity series of metals is given below:
Reaction 1 is possible because copper is more reactive than silver and it will displace silver from silver sulphate to form copper sulphate and silver. Reaction 2 is not possible because zinc is less reactive than aluminium and it will not be able to displace aluminium from aluminium sulphate. Reaction 3 is correct as iron, being more reactive than lead, will displace lead from lead sulphate to form iron sulphate and lead. Reaction 4 is also correct as aluminium, being more reactive than iron, will react with iron sulphate to form aluminium sulphate and iron.
Question 45 1.25 / -0
Since the enthalpy of elements in their standard state is taken to be zero, the heat of formation of a compound
Solution
Since the enthalpy of elements in their standard state is taken to be zero, the heat of formation of a compound (
) may be positive or negative
Question 46 1.25 / -0
Besides urination, another important activity in which water is substantially lost from the body is
Solution
Besides urination, another important activity in which water is substantially lost from the body is expiration. Water is lost in sweat, in expired air, and in urine. Under normal conditions, the amount of water lost in the faeces is relatively small.
Question 47 1.25 / -0
Which part of the nerve cell contains a nucleus?
Solution
The cell body contains the necessary structures for keeping the neuron functional. It includes the nucleus, mitochondria, and other organelles.
Question 48 1.25 / -0
A human male bearing an allele for a trait on the X chromosome is termed as
Solution
Human males are termed as hemizygous for any X-chromosome genes, meaning that there are only half (hemi) as many alleles as normally present for a diploid individual. As a result, if males inherit X-linked recessive trait from their mothers, they will show the recessive phenotype.
Question 49 1.25 / -0
For a cross between a tall plant with round seeds (TTRR) and a short plant with wrinkled seeds (ttrr), the F1 plants will be
Question 50 1.25 / -0
In the cell cycle, when will the synthesis of RNA be stopped?
Solution
DNA condensation takes place during the M phase and RNA synthesis stops.
Question 51 1.25 / -0
Gram-positive bacteria are those which
Solution
The bacteria retain blue colour, which is due to low lipid contents in their cell wall.
Question 52 1.25 / -0
Match the following:
LIST - A LIST - B i. Involucre A. Cymose ii. Ray florets B. Acacia iii. Centrifugal C. Bract iv. Phyllode D. Launaea
Solution
Involucre is a group of bracts enveloping a condensed inflorescence. Launaea pinnatifida.
Question 53 1.25 / -0
A diabetic patient is on insulin. Which of the following cells might have been damaged in this person?
Solution
It secretes insulin. Insulin causes cells in the liver, skeletal muscle and fat tissue to take up glucose from the blood and thus reduces the blood glucose level.
Question 54 1.25 / -0
Haemodialysis is a treatment option for patients with malfunctions of
Solution
Haemodialysis, commonly called kidney dialysis or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally.
Question 55 1.25 / -0
Bile salts
Solution
Bile salts emulsify fats and solubilise them. This aids in digestion and absorption of fats.
Question 56 1.25 / -0
Which of the following pairs is a mismatch?
Solution
Roots show movements towards water in soil to receive water. Therefore, roots are positively hydrotropic and not negatively hydrotropic.
Question 57 1.25 / -0
Lacteals are tiny lymphatic vessels. Where are these found in the body?
Solution
A lacteal is a lymphatic capillary that absorbs dietary fats in the villi of the small intestine. Triglycerides are emulsified by bile and hydrolysed by the enzyme lipase, resulting in a mixture of fatty acids, di- and monoglycerides.
Question 58 1.25 / -0
Hyposecretion of which hormone causes diabetes?
Solution
Insulin is a hormone produced by pancreas that helps in regulating blood sugar level. Diabetes is caused when the pancreas do not produce enough insulin.
Question 59 1.25 / -0
Which of the following structures will not be visible in the section of a hyaline cartilage?
Solution
Haversian canals are a series of microscopic channels in the outermost region of bone called cortical bone that allow blood vessels and nerves to travel through them. Each haversian canal generally contains one or two capillaries and nerve fibres.
Question 60 1.25 / -0
Which of the following cell structures is/are associated with oxidative phosphorylation?
Solution
Oxidative phosphorylation is the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to O2 by a series of electron carriers. This process, which takes place in mitochondria, is the major source of ATP in aerobic organisms.
Question 61 1.25 / -0
If f(x) = x3 - 4x + p and f(0) and f(1) have opposite signs, then which of the following is necessarily true?
Solution
f(0) = p and f(1) = p - 3
Since f(0) and f(1) have opposite signs, so if p < 0, then p - 3 > 0, i.e. p > 3, which is not possible.
Or, p > 0 and p - 3 < 0
p < 3
0 < p < 3
Hence, answer option 2 is correct.
Question 62 1.25 / -0
Given four lines with equations x + 2y – 3 = 0, 3x + 4y – 7 = 0, 2x + 3y – 4 = 0 and 4x + 5y – 6 = 0. Then
Solution
x + 2y - 3 = 0, 2x + 3y - 4 = 0
Question 63 1.25 / -0
In the given figure, O is the centre of the circle and AE is a diameter. If AB = BC and
BFC = 25°, find the value of
ABC.
Solution
Angles subtended by equal chords are equal.
AFB = 25° =
BFC
In the cyclic quadrilateral ABCF,
AFC = 25° + 25° = 50°
ABC = 180° - 50° = 130° (because the sum of opposite angles of a cyclic quadrilateral is 180°)
Question 64 1.25 / -0
In the figure given below, AB is a diameter of the circle, TD is a tangent to the circle and AB = 2AD. If
AHD = 36°
and
DBA = 30°, then what is the measure of
CDT?
Solution
BDA = 90°,
AHD = 36°, AB = 2AD
DBA = 30°
So,
DCA = 30°
(because angles by the same segment at the circumference are equal)
Now, we know that triangle ABD is a right triangle.
So,
DAB = 60° and
DBA = 30°
TDA =
DBA (Angles in alternate segment)
DCA = 30°
CDH = 6°
(Exterior angle = Sum of interior opposite triangles for triangle DCH)
CDT = 6 + 90 + 30 = 126°
Hence, 126° is the correct answer.
Question 65 1.25 / -0
Directions:
Solution
One root is i - 1 & other root should be - i - 1 as coefficients are rational.2 2 = 22 + 2x + 2 = 0
Question 66 1.25 / -0
A solid square plate is spun around different axes with the same angular speed. In which of the following choices of axis of rotation will the kinetic energy of the plate be the largest?
Solution
Distance between centre of mass and inertial axes is the largest. So, torque will be high and kinetic energy will be high.
Question 67 1.25 / -0
An object is placed 0.40 m from one of the two lenses L
1 and L
2 of focal lengths 0.20 m and 0.10 m, respectively as depicted in the figure. The separation between the lenses is 0.30 m.
Solution
Correct Answer: Infinity
Calculation for the first lens L1 : ⇒ v = 0.40
Now for lens L2 : ⇒ u = 0.40 - 0.30 = 0.10
⇒ f = -0.10
From lens formula,
⇒ v = infinite
Question 68 1.25 / -0
Directions: Study the given electric circuit diagram.
If the voltage between points A and B is 10 V. The voltage between B and C will be
Solution
The voltage between points A and B = 10 V
Resistance between points A and B = 20
∴ Current flowing, I =
A
The same current will flow between B and C.
Equivalent resistance between points B and C
= 15
+ 25
= 40
∴ Voltage between points B and C =
× 40 V = 20 V
Question 69 1.25 / -0
A gun fires bullets each of mass 1 g with velocity of 10 ms-1 by exerting a constant force of 5 g weight. Then the number of bullets fired per second is-2 )
Solution
Mass of each bullet (m) = 1 g = 0.001 kg
Velocity of bullet (v) = 10 ms-1
Applied force (F) = 5 g wt.
=
× 10 N
= 0.05 N
Let n bullets are fired per second, then
Force = rate of change of linear momentum
ie, F = n × mv
∴ Number of bullets fired per second
(n) =
=
= 5
Question 70 1.25 / -0
The excess of pressure inside the first soap bubble is three times that inside the second bubble. The ratio of volume of the first to that of the second bubble is
Solution
Excess of pressure inside a soap bubble
P =
or
Given P
1 = 3 P
2 ∴
or
Therefore, ratio of volumes of bubbles
=
∴ V
1 : V
2 = 1 : 27
Question 71 1.25 / -0
BF3 is a
Solution
According to Lewis, acids are those species which can accept lone pair of electrons. BF3 has incomplete octet; so it acts as Lewis acid.
Question 72 1.25 / -0
Identify product 'Z' in the following reaction scheme:
C
6 H
5 NH
2
Question 73 1.25 / -0
a K
2 Cr
2 O
7 + b KCl + c H
2 SO
4 x CrO
2 Cl
2 + y KHSO
4 + z H
2 O
The above equation gets balanced when
Question 74 1.25 / -0
The percentage of s character of the hybrid orbitals of carbon in ethane, ethene and ethyne, respectively is
Solution
Hybridisations of the carbon atom in case of ethane is sp3 and each hybrid orbital has 25% s-character.2 and each hybrid orbital has 33% s-character.
Question 75 1.25 / -0
One mole of a compound AB reacts with one mole of a compound CD according to the equation AB + CD
AD + CB. When equilibrium was established, it was found that 3/4 mol each of reactants AB and CD had been converted to AD and CB, respectively. There was no change in volume. The equilibrium constant for the reaction is
Question 76 1.25 / -0
Which of the following is the correct set of vestigial organs?
Solution
Vestigiality is the retention during the process of sexual reproduction of genetically determined structures or attributes that have lost some or all of their ancestral function in a given species. Some of the vestigial organs in humans are: muscles of the ear; wisdom teeth; the appendix; the tail bone; body hair; and the semilunar fold. Some examples of vestigial organs in other animals are: wings of kiwi, splint bone of horse and hind limbs of python.
Question 77 1.25 / -0
A couple has a daughter suffering from Tay Sachs disease, and 4 normal children. Neither parent nor any of the four biological grandparents of the affected daughter had this disease. The most likely genetic condition leading to Tay Sachs disease is
Solution
It must be recessive because both parents are normal, but one or both parents must have passed the disease allele to their daughter. Since one or both parents are heterozygous and are not affected by the Tay Sachs allele, the disease must be recessive.
Question 78 1.25 / -0
What is the pattern of connection of two strands of DNA?
Solution
A makes a double bond with T and C forms a triple bond with G.
Question 79 1.25 / -0
Mr. X, while drowning, simply failed to try to save himself, even though he was a good swimmer. He must have suffered from ________ neurological disorder.
Solution
Cerebral palsy (CP) is a group of disorders that affect a person's ability to move and maintain balance and posture. CP is the most common motor disability in childhood. Cerebral means having to do with the brain. 'Palsy' means 'weakness or problems with using the muscles'. People with cerebral palsy have various motor problems, such as spasticity, paralysis and even seizures.
Question 80 1.25 / -0
Which of the following is the inflammation of the lining of the rectal mucosa?
Solution
Proctitis is inflammation of the lining of the rectum, the lower end of the large intestine leading to the anus.
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