Question # 1

Two artificial satellites of unequal masses are revolving in a circular orbit around the earth with a constant speed. Their time periods:

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Will be different

Will depend on their masses

Will be same

Will depend upon the place of their projection

The number of electrons in a nucleus X of atomic number Z and mass number A is:

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A

W

Z

Y

A particular wavelength received from a galaxy is measured on earth and isfound to be 5% more than that its wave length on earth. Hence galaxy is

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Moving towards earth

Going away from earth

Stationary with respect to earth

None

The electron is a cathode-ray tube are accelerated from cathode to anode by a potential differenceof 2000 V. If this p.d is increased to 8000 V, the electrons will arrive at the anode with:

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Twice the kinetic energy and four times the velocity

Four times the kinetic energy and twice the velocity

Four times the kinetic energy and sixteen times the velocity

Sixteen times the kinetic energy and four times the velocity

A total charge of 100C flows through 12W bulb in a time of 50 second. Which is the potential difference across the bulb during this time?

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0.12V

6.0V

2.0V

24V

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

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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

A body of mass m kg is lifted by a man to a height of one meter in 30 sec. Another man lifts the same mass to the same height in 60 sec. The work done by them are in the ratio

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1: 2

1: 1

2: 1

4: 1

Moving photons posses:

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Energy

Momentum

Wavelength

All of these

When a particle moves in a circle the angle between it linear velocity and the angular velocity is always

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0°

180°

90°

none of them

Geo stationary satellite remains

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Stationary

Both "A" & "B"

Appear

None of them

When the radioactive nucleus emits a beta particle, the proton neutron ration:

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increases by one

Remains same

Decreases by one

Decreases by four

In Compton effect, it was considered that X-rays consist of:

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Electrons

Positrons

Photons

All of these

When resistances are connected in Parallel, the effective resistance will be

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Product of the reciprocals of the individual resistances

Product of the individual resistances

Sum of the reciprocals of the individual resistances

Sum of the individual resistances

When a person lifts a body from ground work done by lifting force is?

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Positive

Negative

Zero

Half of positive maximum

What will be the number of photons emitted per second by 25 W source of monochromatic light of wavelength 600 nm:

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7.5 × 1017

7.5 × 1019

5.5 × 1019

5.5 × 1017

In photo electric cell, the photo electric current

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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 of the following does not have the same units:

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Work

Heat

Kinetic energy

Power

If an electron is accelerated such that its K.E is 4 times of its rest mass energythen thetotal relativistic energy of electrons is about

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5 × 10–12 J

4 × 10–13 J

3 × 10–13 J

6 × 10–12 J

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

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halved

doubled

remain unchanged

becomes four times

The centre of gravity of a triangular plate is at

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On end of the plate

The midpoint of any side of the plate

The ratio of the longest and shortest wavelength of the Lyman series is approximately:

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4/3

9/4

9/5

16/7

The unit of gain (G) for non-inverting amplifier is

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Ampere

ohm

Volt

None of these

Swimming is possible on account of

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1^st law of motion

2^nd law of motion

3^rd law of motion

Newton’s law of Gravitation

For a particle in circular motion the centripetal acceleration

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may be more or less than its tangential acceleration

equal to its tangential acceleration a

more than its tangential acceleration

less than its tangential acceleration

A 4 m long string fixed at its ends resonate in 4 segments. The wavelength of the waveis:

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4m

0.5m

2m

0.25 m

Only those processes are probable to take place for which entropy os the system:

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Increases

Remains constant

Both A and B are correct

None of above

Wavelength of the wave is the distance between the particles of the medium having adifference of:

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Zero

n

2n

𝜋2

The angular momentum of a body changes from 30 J-S to 50 J-S in 0.5 sec. The torque acting on it is

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40 N-m

100 N-m

50 N-m

150 N-m

The emf of a cell of negligible internal resistance is 2V. It is connected to the series combination of 𝟐𝛀, 𝟑𝛀 𝐚𝐧𝐝 𝟓𝛀 resistance. The potential difference across 𝟑𝛀 resistance will be in volt:

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0.6

2/3

3

6

The diodes works on

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A.C

D.C

both A and B

None of these

An electron and a proton are accelerated through the same potential. If their masses are me and mp respectively, then the ratio of their de-Broglie wavelength is:

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1

mp/me

me/mp

The angle of projection, at which the range of projectile would become half of its maximum value.

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45Degree

30Degree

15Degree

60 Degree

The magnetic field due to the electric current in a conducting wire is:

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Towards the centre of the conducting wire

Circular around the conducting wire

In the direction of the electric current

In the direction opposite to the electric current

The number of molecules in one mole of gas is equal to:

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Avogadro number N_A

Gas constant R

Boltzmann constant k

None of these

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 :

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140days

45days

87days

90days

Two charges of equal magnitudes and at a distance r exert a force F on each other. If the charges are halved and distance between them is doubled, then the new force acting on each charge is:

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F/8

F/4

F/16

4F

The energy stored in wound watch spring is

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K.E.

P.E.

heat energy

chemical energy

Number of spark plugs needed in diesel engine is:

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Four

Five

Six

None of these

When a radioactive nucleus emits a 𝖰 −paritcles, the mass number of the atom:

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Increases by one

Decreases by one

Remains the same

Decreases by four

The maximum kinetic energy of emitted photoelectrons depends upon:

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The intensity of incident light

Frequency of the incident light

Temperature of the surface

All of above

The Balmer series is found in the spectrum of:

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Hydrogen

Nitrogen

Oxygen

All