Maharashtra Board SSC 10th Exam 2024 Science & Technology (Part I) Most Important Question Answers

Maharashtra SSC Class 10 exams are 18th and you have very little time left for Science & Technology (Part I) exam. Therefore, we are providing the most important marking wise answer type questions in this article. You can study them well and get good marks in your examination.

Important short answer type questions and long answer type questions are provided in this article. Most Important Short and Long Questions Answers are an important part of your Science & Technology (Part I) exam to score good marks. Mastering them can boost your confidence and score important marks. These questions cover various topics of Science & Technology (Part I) syllabus.

Maharashtra Board Science & Technology (Part I) Most Important Questions Answers

Q1. Choose the correct option in the multiple choice answer for the following questions : (1 mark each)

(1) A ___________ is necessary to change the speed as well as the direction of motion of an object.

(a) force
(b) inertia
(c) momentum
(d) motion

Ans. (a) force 

(2) The orbit of a planet revolving around a star is ___________ .

(a) circular
(b) linear
(c) towards the focal point
(d) elliptical

Ans. (d) elliptical

(3) The square of its period of revolution around the sun is directly proportional to the ___________ of the mean distance of a planet from the sun.

(a) square
(b) square root
(c) cube
(d) cube root

Ans. (c) cube

(4) The ___________ force is much weaker than other forces in nature.

(a) gravitational
(b) electromagnetic
(c) nuclear force
(d) inter molecular

Ans. (a) gravitational

(5) The value of gravitational acceleration (g) is _____________ .

(a) highest at the poles
(b) highest at the equator
(c) same everywhere on the surface of the earth
(d) lowest at the poles

Ans. (a) highest at the poles

(6) The free fall of an object is possible only in ___________ .

(a) air
(b) vacuum
(c) on the surface of earth
(d) None of these

Ans. (b) vacuum

(7) At the time of Mendeleev ____________ elements were known.

(a) 56
(b) 65
(c) 63
(d) 118

Ans. (c) 63

(8) In Mendeleev's periodic table eka- silicon was later named as _____________ .

(a) Scandium
(b) Gallium
(c) Germanium
(d) Thorium

Ans. (c) Germanium

(9) The groups 1 and 2 constitute the _____________ block.

(a) s
(b) p
(c) d
(d) d

Ans. (a) s

(10) Which pair of atomic numbers represents elements in the same group ?

(a) 11,19
(b) 6,12
(c) 4,16
(d) 8,17

Ans. (a) 11,19

(11) which among the following elements would lose an electron easily ?

(a) Mg
(b) Na
(c) Al
(d) Cl

Ans. (b) Na

(12) Which among the following is the largest element ?

(a) Na
(b) Mg
(c) K
(d) Ca

Ans. (c) K

(13) The unit of electrical power is _____________ .

(a) Volt
(b) Watt
(c) Joul
(d) Ampere

Ans. (b) Watt

(14) In an electric bulb coil of ____________ metal is used.

(a) Copper
(b) Tungsten
(c) Aluminium
(d) Iron

Ans. (b) Tungsten

(15) The electricity bill specifies the usage in ____________ .

(a) Kilowatt
(b) Joule
(c) Volt
(d) Unit

Ans. (d) Unit

(16) The frequency of AC is ____________ Hz

(a) 20Hz
(b) 50Hz
(c) 25Hz
(d) 75Hz

Ans. (b) 50Hz

(17) These days when current in the circuit suddenly increases ____________ switches are used.

(a) MCA
(b) MCC
(c) MCD
(d) MCB

Ans. (d) MCB

(18) A coil of an alloy ____________ is used in electric heater cooker as a resistor.

(a) Stainless steel
(b) Nichrome
(c) Copper
(d) Bronze

Ans. (b) Nichrome

Q2. Write Scientific reasons. (2 marks each)

1. When we drop a feather and a stone at the same time from a height the stone reach the earth faster than a feather.

Ans.

1. When we drop a feather and a heavy stone at the same time from a height, the feather experiences a buoyant force and a frictional force due to air and therefore floats and reaches the ground slowly.

2. But, the buoyant and frictional forces on the stone are much less than the weight of the stone and does not affect the speed of the stone much.

3. Hence, when we drop a feather and a stone at the same time from a height, the stone reach the earth faster than a feather.

2. Mendeleev kept vacant places in the periodic table.

Ans.

1. In Mendeleev’s periodic table, the elements are arranged in increasing order of their atomic masses such that chemically similar elements are placed together in a group.

2. However, while arranging the elements, Mendeleev kept vacant places in the periodic table for elements not discovered till then.

3. Three of these unknown elements were given the names eka-boron, ekaaluminium and eka-silicon from the known neighbours.

4. The atomic masses of these elements were indicated as 44, 68 and 72, respectively. He also predicted their properties.

3. Fish can survive even in frozen ponds in cold regions.

Ans.

1. In cold climate, temperature of water in ponds and lakes starts falling.

2. On getting colder, water contracts. As a result, the density of water increases and it goes down. To replace it, warmer water from below rises up. This process continues till temperature of water at the bottom of pond becomes 4 °C.

3. Water, due to its anomalous behaviour possesses maximum density at 4 °C.

4. If the temperature lowers further, ice is formed at the surface of a pond with water below it.

5. Ice is a poor conductor of heat blocks the further heat exchange between the atmosphere and water in the pond.

6. This prevents freezing of water below surface of ponds or lakes enabling survival of fishes.

4. Simple microscope is used for watch repairs.

Ans.

1. A magnification of about 20 times is obtained by a simple microscope.

2. When an object is placed within the focal length of a convex lens, one gets a magnified and erect image of the object.

3. Thus, the watch repairer can see the minute parts of the watch more clearly with the help of a simple microscope than the naked eye, without any strain on the eye.

4. Hence, a simple microscope is used for watch repairs.

5. One can sense colours only in bright light.

Ans. 

1. The light sensitive screen of the eye, called the retina, has two types of light sensitive cells.

2. Rod cells are concerned with vision in dim light and cone cells are responsible for the vision in presence of light.

3. Cone cells are also concerned with colour perception. They do not respond to dim light or no light.

4. Thus, the knowledge of the colour is possible in presence of light and not in dark.

5. Hence, we can identify and differentiate colours in presence of light.

6. The movie cannot be enjoyed if it is too close to the screen in the cinema.

Ans.

1. The nearer someone is sitting to the screen of the cinema hall; the more is the intensity of light falling on the eye.

2. Thus, the pupil has to contract a lot, which causes a strain in the eye.

3. Hence, one cannot enjoy watching a movie from a very short distance from the screen in a cinema hall.

7. We can not clearly see an object kept at a distance less than 25 cm from the eye.

Ans. 

1. The muscles attached to the eye lens (ciliary muscles) help in fine adjustments of the focal length of the lens.

2. The capacity of these muscles to contract or relax to adjust the focal length (i.e., power of accommodation) has a limit.

3. The minimum distance of an object from a normal eye for which the eye lens can decrease its focal length to the least possible value, is 25 cm.

4. Hence, we cannot clearly see an object kept at a distance less than 25 cm from the eye.

Q3. Answer the Following. (3 marks each)

(1) Write the Kepler's law.

Ans.

1. Kepler’s first law : The orbit of a planet is an ellipse with the sun at one of the foci.

2. Kepler’s second law : The line joining the planet and the sun sweeps equal areas in equal intervals of time.

3. Kepler’s third law : The square of the orbital period of revolution of a planet around the Sun is directly proportional to the cube of the mean distance of the planet from the Sun.

(2) State Newton's universal law of gravitation. Express it with the mathematical form of force of gravitation ?

Ans. 

1. Statement : Gravitational force between two bodies in the universe is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

2. The mathematical equation for the law is given as, F = G m₁m₂/r² where G is universal gravitational constant, m₁ and m₂ are masses and r is the distance between two masses.

(3) A ball falls off a table and reaches the ground in 1 s. Assuming g = 10 m/s², calculate its speed on reaching the ground and the height of the table ?

Ans.

(1) Velocity on reaching the ground

Ans. 

Given : Mass on earth (me) = 5 kg, weight on earth (W_e) = 49 N,

acceleration due to gravity on moon (g_m) = 9.8/6 m/s² = 1.6333 m/s²

To find : Mass (m_m), weight (W_m) on moon

Formula : W_m = m_mg_m

Calculation : The mass of the object is independent of gravity and remains unchanged i.e., 5 kg.

From formula,

W_m = 5 × 1.6333

∴ W_m = 8.1665 N ≈ 8.17 N

On moon, the mass of the object is 5 kg and the weight is 8.17 N.

(5) An object thrown vertically upwards reaches a height of 500 m. What was its initial velocity ? How long will the object take to come back to the earth ? Assume g = 10

Ans. 

From newton’s third equation of the motion;

V² = u² + 2as

Where;

V = Final velocity;

U = initial velocity;

T = time taken;

S = distance travelled;

A = acceleration;

According to our question;

The figure below illustrates the situation given in the question

V = 0 (Velocity at maximum height is zero);

S = 500m ;

A = -10 m/s² (because when object will be going up the acceleration due to gravity will be acting downwards to make object to fall. Hence by sign convention direction of motion and acceleration is opposite therefore a is negative);
Putting the above values we get

0² = u² + (2 x (-10) x 500)

0 = u² - 10000

u² = 10000

⇒ u = √10000 =100

Therefore initial velocity is 100m/s.

From the Newton’s first law of motion;
v = u + at

Where symbols have there usual meanings as above;

v = 0 (velocity at maximum height is zero);

u = initial velocity = 100m/s;

a = - 10m/s² (because when object will be going up the acceleration due to gravity will be acting downwards to make object to fall. Hence by sign convention direction of motion and acceleration is opposite therefore a is negative);
Putting the values we get;

0 = 100 + ( -10t )

= 100 = 10t

t = 100/10 = 10s

Now we know that time required by an object to go up is same as time required to come down.
Therefore;

Total time = time of ascent + time of descent

= 10 + 10 = 20 s

Hence total time to come back to earth is 20 seconds.

Q4. Answer the following questions. (5 Marks each)

(1) Read the given passage carefully and answer the questions.

We know that the gravitational force of the earth is applied to all objects.This force was used even when you were holding a stone in your hand. But the force you were pushing in the opposite direction with your hand was balancing it so that the stone was stable.When you let go of the hand ,only gravitational force is applied to the stone, so the stone falls under its influence. When an object is moving only under the influence of gravitational motion, that motion is called free fall,that is the stone falls. In free fall,the initial velocity is zero and it is increased due to gravitational acceleration over time. At the time of free fall on the earth , the friction of the air opposes the motion of the object. So in the true sense free fall cannot happen in the air. It can happen only in vacuum.

(A) Complete the following statement by choosing the right option.

The stone held in the hand is stable because on it ....

(a) two unbalanced forces are exerted.
(b) only the gravitational force of the earth is exerted.
(c) gravitational force of the earth is not exerted.
(d) two balanced forces are exerted.

Ans. (d) two balanced forces are exerted.

(B) Why does free fall not happen on the earth ?

Ans. At the time of free fall on the earth, in addition to gravitational force, the object experiences force of friction due to air. Thus, the free fall cannot happen on the earth.

(C) Why does the velocity of the object increase during the free fall ?

Ans. The velocity of the object increases due to acceleration due to the gravity of the earth.

(D) Which type of force exerts on the object during free fall ?

Ans. During free fall only gravitational force is exerted on the object.

(E) Why does free fall happen only in vacuum ?

Ans. Object experiences free fall when the only force acting on the object is a gravitational force. During free fall in air, the frictional force due to air opposes the motion of the object and a buoyant force also acts on the object. Thus, true free fall is possible only in a vacuum.

(2) XY Compound formed by X (Atomic number 11) and Y (Atomic number 17) then answer the questions given below.

(A) Determine the position of the element X and Y in the modern periodic table. 

Ans. Element X is placed in group 1 and period 3. Element Y is placed in group 17 and period 3.

(B) Which type of elements X and Y are metals, nonmetals or metalloids ? 

Ans. Element X is a metal while element Y is a nonmetal.

(C) From which block the elements X and Y are ? 

Ans. Element X belongs to s-block and element Y belongs to p-block.

(D) Determine the electronic configuration and valency of these elements.

Ans. Electronic configuration of element X is (2, 8, 1). Its valency is 1. Electronic configuration of element Y is (2, 8, 7). Its valency is 1.

-

Maharashtra Board Class 10 Study Material