Question # 1

In a gravitational field when work done by gravity is negative then

Choose an answer

P.E increases

P.E decrease

None

P.E remains same

Which row is correct for fission and for fusion?

Choose an answer

Produces larger nuclei

Produces smaller nuclei

Intensity of light from a point source at the edge of unit sphere will be:

Choose an answer

𝑃

P(4π)

4𝜋

An electric room radiator, which operates at 50V has resistance of 50 Ω. Power of the radiator is approximately:

Choose an answer

100W

50W

450W

1000W

A point on the rim of a wheel 4m in diameter has a velocity of 1600 cm s-1. The angular velocity of the wheel is

Choose an answer

2 rad s^-1

4 rad s^-1

6 rad s^-1

8 rad s^-1

Avogadro number is known as number of molecules in:

Choose an answer

One kg of a substance

Unit volume of a substance

One mole of a substance

None of these

If the stone is thrown up vertically and return to ground, its potential energy is maximum

Choose an answer

during the upward journey

at the maximum height

at the bottom

For X-rays which of the following is not correct:

Choose an answer

Cause of ionization in air when they pass through it

Can be deflected by electric and magnetic fields

Can be used to detect flaws in metal casting

Travel with the speed of light

Area under Q-V graph for a capacitor represents

Choose an answer

Charged stored

Energy stored

Electric field strength

Potential difference

In 420 days, the activity of a sample of polonium (Po) fell to one-eight of its initial value. The half-life of polonium is :

Choose an answer

140days

45days

87days

90days

In the absence of air resistance, a stone is thrown from P and follows a parabolic path in which the highest point reached is T. The vertical component of acceleration of stone is:

Choose an answer

Zero at T

Greatest at T

) Greatest at P

the same at P as at T

Which one is the case when the wavelength is actually changed?

Choose an answer

When source move relative to observer

When observer move relative to source

When observer moves around a stationary source at the center of circle

When the relative displacement between source and observer is zero

If the momentum of a body is increased n times, its kinetic energy increases:

Choose an answer

n times

2 n times

√𝑛 times

n 2 time

If a transverse wave has a speed of 10 m/ sec and frequency of 10 cycle/ sec itswavelength is:

Choose an answer

1 m

10^-2 cm

10 m

10 cm

A man pushes a wall and fails to displace it. He does:

Choose an answer

Negative work

Positive but not maximum work

No work at all

Maximum work

A process which is carried at constant temperature and Boyle's law can be applied is called:

Choose an answer

Adiabatic process

Isothermal process

Isochoric process

None of these

If a rotating body is moving counter clockwise, direction of angular velocity will be

Choose an answer

along linear velocity

towards the center

along the axis of rotation

away from center

In a closed organ pipe, the fundamental frequency is f. What will be the ratio of thefrequencies of the next three overtones?

Choose an answer

2 : 3 : 4

3 : 7 : 11

3 : 4 : 5

3 : 5 : 7

How many photons per second does a one-watt bulb emit if its efficiency is 10% and the wavelength of light is 500 nm:

Choose an answer

2.53 × 1017

2.53 × 1019

7.5 × 1019

7.5 × 1017

The time period of a geostationary satellite above the surface of the earth is.

Choose an answer

24 hours

12 hours

365 days

none of these

In photoelectric effect experiment, stopping potential depend upon

Choose an answer

Intensity of light

Frequency of light

Photoelectric current

Both A and B

The potential difference applied to an X-rays tube is increased. As a result, in the emitted radiation

Choose an answer

The intensity increases

The minimum wavelength decrease

The intensity remains unchanged

Both B & C

In photo electric cell, the photo electric current

Choose an answer

Decreases with increase in frequency of light

Depends on intensity and frequency of light

Does not depend upon the frequency of light and but depends upon intensity of light

Increases with increase in frequency of light

Which one of the following statements regarding electrostatics is wrong?

Choose an answer

Charge is conserved

Charge is quantized

There is no field near an isolated charge at rest

A moving charge produces both electric and magnetic fields

Truth of kinetic energy theory is confirmed by:

Choose an answer

Diffusion of gases

Brownian motion

Both A and B

None of these

In photoelectric effect, electrons are emitted with:

Choose an answer

Same energy

Different energies

Both (a) & (b)

Intermittent energies

A body moves a distance of 10 m along a straight line under the action of a force of 5 N. If the work done is 25 joules, the angle which the force makes with the direction of motion of the body is?

Choose an answer

0 Degree

30 Degree

60 Degree

90 Degree

What happens to the centripetal acceleration of a particle, when its speed is doubled and angular velocity is halved?

Choose an answer

halved

doubled

remain unchanged

becomes four times

The momentum of the moving photon is:

Choose an answer

Zero

ℎ

𝜆

ℎ𝜆

Photoelectric effect and Compton effect prove the:

Choose an answer

Wave nature of light

Particle nature of light

Dual nature of light

A radioactive substance has a half-life of 4 months. Three-fourths of the substance will decay in:

Choose an answer

5months

6months

8months

7months

In a one-dimensional elastic collision, the relative velocity of approach before collision is equal to:

Choose an answer

Sum of the velocities of the bodies

e times the relative velocity of separation after collision

1⁄𝑒 times the relative velocity of separation after collision

relative velocity of separation after collision

What is the momentum of a photon of light of wavelength 500 nm in kgm/s:

Choose an answer

1.32 × 10−21

1.32 × 10−23

1.32 × 10−25

1.32 × 10−27

The equation PVr = Constant applies to:

Choose an answer

Isothermal process

Adiabatic process

Isobaric process

None of these

The efficiency of a particle heat engine:

Choose an answer

can be 100%

Cannot be 100%

Is always zero

None of these

A closed organ pipe and an open organ pipe have their first overtone identical infrequency. Their lengths are in ratio

Choose an answer

3:4

1:2

2:3

3:5

The relative permittivity of air is

Choose an answer

1

3.7

7.8

1.0006

The coulomb’s law is valid for the charges which are:

Choose an answer

Moving and point charges

Stationary and point charges

Moving and non-point charges

Stationary and large size charges

The direction of angular velocity is along

Choose an answer

Tangent to the circle

Axis of rotation

Inward the radius

Out ward of the radius

The centre of gravity of a triangular plate is at

Choose an answer

On end of the plate

The midpoint of any side of the plate