Question # 1

A wave which consists of a single, non-repetitive disturbance is called a

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Continuous wave

Longitudinal wave

Pulse

Transverse wave

You lift a suit case from the floor and keep it on a table. The work done by you on the suitcase does not depend on

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the path taken by the suitcase

weight of the suitcase

initial and final position

None

According to Bohr’s theory, a line in the Ballmer series arises when the electron jumps from any of the higher orbits to the orbit with quantum number:

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1

2

3

4

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

A rider uses Motorcycle safety helmet that extends the time of collision during accident hence decreasing the

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Change of collisio

Force acting

Velocity

Impulse

The activity of a radioactive sample is 1.6 curie and half-life is 2.5 days. Its activity after 10 days will be:

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0.8 Curie

0.1Curie

0.4 Curie

0.16 Curie

A radioactive isotope 𝟐𝟑𝟖 𝑼 decays consecutively to 𝟐𝟑𝟒 𝑼 the particles emitted are:

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One 𝛼 and one 𝛽

Two 𝛼 and one 𝛽

e 𝛼 and two 𝛽

Two 𝛼 and two 𝛽

In a full wave rectifier, the diode conducts during

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Both halves of the input cycle

A portion of the positive half cycle of the input

Positive half cycle of the input

Both halves of the input cycle

When two objects come to common temperature, the body is said to be in:

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Static equilibrium

Dynamic equilibrium

Thermal equilibrium

None of these

The Balmer series is found in the spectrum of:

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Hydrogen

Nitrogen

Oxygen

All

The value of universal gas constant R is:

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8.314 J/K mole K

8314 J/ mole K

8.314 J/ mole K

None of these

A man weighing 500 N carries a load of 10 kg to the top of a building in 4 minutes. The work done by the man is 6 × 𝟏𝟎⁴ J. If he carries the same load in 8 minutes, the work done by the man will be:

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3 × 10⁴ J

6 × 10⁴J

9 × 10⁴J

12× 10⁴ J

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

Ratio of dimension of K.E and power is:

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1:1

T:1

1:T

M:J

Newton’s third law concerns the forces of interaction between two bodies. Which of the following statement relating to the third law is not correct:

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The two forces must be the same type

The two forces must act on different bodies

The two forces are always opposite in direction

The two forces are equal and opposite so the bodies are in equilibrium

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

Speedometer of an automobile measures

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Average velocity

Instantaneous velocity

Acceleration

Instantaneous speed

The magnetic field produced due to the current in a straight wire is proportionalto the :

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Electric current

Conducting material

Length of the wire

Diameter of the wire

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the Stopping distance will be:

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The same

Doubled

Halved

Four times

In an explosion a body breaks up into two pieces of unequal masses. In this:

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Both parts will have numerically equal momentum

Lighter part will have more momentum

Heavier part will have more momentum

Both parts will have equal kinetic energy

A stone is thrown upwards it returns to ground describing a parabolic path which of the following remains constant:

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Speed of the ball

Kinetic energy of the ball

Vertical component of velocity

) Horizontal component of velocity

De-Broglie received the Nobel prize on his work on:

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Wave nature of particle

Corpuscular nature of wave

Dual nature of particle

All of them

No entropy change is associated with:

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Isothermal

Adiabatic process

Isobaric process

None of them

The maximum energy of the photoelectrons depends upon:

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Frequency of incident light

Intensity of incident light

Nature of metal

Both (a) & (c)

The maximum energy of the photoelectrons can be determined by making the:

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Anode positive

Anode negative

Cathode positive

Both (b) & (c)

Carnot engine is ____________ heat engine.

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A reversible

An irreversible

An ideal

Both A and C

A count rate 240 per minute reduces to 30 counts per min in 1 hour. The half-life of source is:

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20min

60min

80min

90min

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

In full wave rectification by bridge the number of diodes required are

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3

4

2

5

In an ideal gas, the molecules have:

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Kinetic energy only

Potential energy only

Both KE and PE

None of these

The ideal gas obey gas law at:

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Low tempratures and high pressures

High temperatures and low pressures

All temperatures and pressures

None of these

. A force "F1" acts on a body through distance "S1" in the direction of motion and does work "W1". Similarly another force "F2" act on same body through distance "S2" but in opposite to the direction of motion and does work "W2". Now if F1 = F2 and S1 = S2 then which statement is correct.

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W1 = W2

W2< W2

W1 > W2

W1 = W2= 0

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

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The intensity increases

The minimum wavelength decrease

The intensity remains unchanged

Both B & C

At constant temperature, if the volume of a given mass of a gas is doubled, then the density of gas becomes:

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Double

Remains constant

Half

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

A sonometer wire 100 cm in length has a fundamental frequency of 330 Hz. Thevelocity of propagation of waves along the wire is

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115m/sec

660m/sec

990m/sec

In order to perform experiment, Davisson and Germer used accelerating voltage of:

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54V

120V

220V

400V

The fusion of hydrogen into helium is more likely to take place:

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At high temperature and high pressure

At high temperature and low pressure

At low temperature and low pressure

At low temperature and high pressure

When an electron in an atom goes from a lower to higher its:

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K.E. increases, P.E. decreases

K.E. increases

P.E increases

K.E. decrease, P.E. increases

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

The efficiency of a particle heat engine:

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can be 100%

Cannot be 100%

Is always zero

None of these