Physics Test 250

Result

Physics Test 250

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
4 / -1

The superposition takes place between two waves of frequency f and amplitude a. The maximum intensity I_max = constant × ____

A
a

B
2a

C
2a²

D
4a²

Solution
Question 2
4 / -1

A particle having mass m and charge q is released from the origin in a region in which electric field and magnetic fields are given by Find the speed of the particle as a function of its z coordinate.

A

B

C

D

Solution

The particle have initial velocity zero, So electric field will be responsible for to move in opposite direction of electric field.

Magnetic force on the particle does not increase the speed of the particle since

Since acceleration is constant applying the one dimensional kinematics equation:
Question 3
4 / -1

An object O is kept in front of a converging lens of focal length 30 cm behind which there is a plane mirror at 15 cm from the lens. Choose the correct statements.

A
The final image is formed at 60 cm from the lens towards right of it.

B
The final image is at 60 cm from lens towards left of it.

C
The final image is real.

D
Both 2 and 3 are correct.

Solution

So from the lens 45 + 15 = 60 cm to the right of it.
Question 4
4 / -1

A TV tower has a height of 50 m. The maximum distance up to which TV transmission can be received is approximately equal to (radius of earth = 6.4 × 10⁶ m)

A
5 km

B
25 km

C
100 km

D
250 km

Solution
Question 5
4 / -1

Which statement(s) is/are true?

(i) Kirchhoff's law is equally applicable to both AC and DC.

(ii) Semiconductors have a positive temperature coefficient of resistance.

(iii) Meter bridge has a greater sensitivity when the resistances of all the four arms of the bridge are of the same order.

(iv) The emf of a cell depends upon the size and area of electrodes.

A
(i) and (iv)

B
(ii) and (iv)

C
(iii) and (iv)

D
None of these

Solution

(i) Kirchhoff's law states that the total current entering into the junction is equal to the total current leaving the junction and it is based on energy conservation. As long as the energy is conserved, it doesn't matters whether the current is AC or DC.

(iv) Emf of a cell depends upon the following factors-

(a) Emf is inversely proportional to the area of electrode.

(b) Emf is directly proportional to the distance of separation between the two electrodes.

(c) Emf is inversely proportional to the temperature of electrodes.

(d) Emf is inversely proportional to the concentation of electrolytes.
Question 6
4 / -1

These question consists of two statements each printed as assertion and reason. While answering these question you are required to choose any one of the following five responses.

Assertion: Small water drops are spherical while bigger water drops are not.

Reason: In small water drops surface tension forces dominate while in bigger water drops gravity forces dominate.

A
If both assertion and reason are correct and reason is the correct explanation of assertion.

B
If both assertion and reason are true but reason is not the correct explanation of assertion.

C
If assertion is true but reason is false.

D
If assertion is false but reason is true.

Solution

Liquid has a tendency to acquire minimum surface area due to surface tension. In gravity free space a drop of any size will be spherical.

In case of gravity, bigger drop will have larger force of gravity which tends to distort the spherical shape of the drop.

Hence, both assertion and reason are correct and reason is the correct explanation of assertion
Question 7
4 / -1

Suppose that the angular velocity of rotation of Earth is increased. Then, as a consequence,

A
weight of the object everywhere on the Earth will decrease

B
weight of the object everywhere on the Earth will increase

C
except at poles, weight of the object on the Earth will decrease

D
there will be no change in weight anywhere on the Earth

Solution

Value of the acceleration due to gravity at any latitude φ,

g' = g - ω²Rcos²φ; where φ is latitude.

There will be no change in gravity at poles as φ = 90°.

At all other points, as ω increases, 'g' will decrease.
Question 8
4 / -1

A man grows into a giant such that his linear dimensions increase by a factor of 9. Assuming that his density remains same, the stress in the leg will change by a factor of:

A
81

B
1/81

C
9

D
1/9

Solution

Hence, the stress in the leg will change by a factor of 9.
Question 9
4 / -1

The dipole moment of a circular loop carrying a current 'I' is 'm' and the magnetic field at the centre of the loop is B₁. When the dipole moment is doubled by keeping the current constant, the magnetic field at the centre of the loop is B₂. The ratio B₁/B₂ is

A
2

B
√3

C
√2

D
1/√2

Solution

The magnetic dipole moment of a current carrying loop of radius R is m and the magnetic dipole moment of a current carrying loop of radius R' is m' .
Question 10
4 / -1

The equivalent capacitance between A and B in the circuit given below is:

A
3.6 μ F

B
2.4 μ F

C
4.9 μ F

D
5.4 μ F

Solution