Question # 1

A boy is travelling from Lahore to Karachi with uniform velocity . Its

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Speed changes

Acceleration changes

Direction of motion changes

Displacement from origin changes

The body at rest may have:

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Energy

Momentum

Speed

Velocity

The motion of molecules in gases i:

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Orderly

Random

Circular

All of these

Truth of kinetic energy theory is confirmed by:

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Diffusion of gases

Brownian motion

Both A and B

None of these

Which of the following is a unit of energy?

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unit

whatt

Horse Power

None of the above

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

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 rate of change of momentum of a molecule is equal to:

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Pressure

Work

Density

Force

Two wires of same material have lengths L and 2L and cross-sectional area 4A and A respectively. the ratio of their specific resistance would be:

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1: 1

1: 8

8: 1

1: 2

The efficiency of a particle heat engine:

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can be 100%

Cannot be 100%

Is always zero

None of these

In photoelectric effect, electrons are emitted:

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Slowly

Intermittently

Both (a) & (b)

Instantly

The ratio of angular speeds of minute hand and hour hand of a watch is:

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1: 12

6: 1

12: 1

1: 6

If the tension in a string stretched between two fixed points is made four times, the frequency of the fundamental harmonic will become:

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Two times

Three times

Four times

Six times

Which one is the correct express of de-Broglie equation for the length of atoms of mass m at temp? T(k=Boltzmann’s constant):

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

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1 m

10^-2 cm

10 m

10 cm

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

A listener observes the frequency “f” of stationary source. If it move toward with 3 times of velocity of sound. Then the apparent frequency of the sound will be

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f

3f

f/2

4f

For the same value of resistors the output of non-inverting amplifier compared to the output of inverting amplifier is, (ignoring phase difference)

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Greater

Equal

Smaller

Undefined

While dealing with the processes i thermodynamics, the working substances is usually:

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Oxygen gas

Hydrogen gas

Ideal gas

None of these

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

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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

For a body moving with constant speed in a horizontal circle, which of the following remains constant?

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Velocity

Centripetal force

Acceleration

Kinetic energy

In photoelectric effect, electrons are emitted with:

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Same energy

Different energies

Both (a) & (b)

Intermittent energies

Car X is traveling at half the speed of car Y. Car X has twice mass of car Y.

Which statement is correct?

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Car X has half the kinetic energy of car Y

Car X has one quarter of the kinetic energy of car Y

Car X has twice the kinetic energy of car Y

The tow cars have the same kinetic energy

Ratio of dimension of K.E and power is:

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1:1

T:1

1:T

M:J

electrons from the surface of a metal when:

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It is heated to a high temperature

Radiation of suitable wavelength falls on it

Electrons of suitable velocity strike it

It is placed in a strong electric field

The law, governing the force between electric charges is known as:

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Ampere’s law

Ohm’s law

Coulomb’s law

Faraday’s law65y7uhnb

A monkey is accelerating down a string whose breaking strength is two third of his weight. The minimumacceleration of the monkey should be

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1/3g

g

2/3 g

0 m/s2

In nuclear fission reaction, when the products are 140X and 94Sr, the number of neutrons emitted is

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1

2

5

9

A photo cell is based on:

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Compton effect

Pair production

Photo cell

All of these

There are two electric bulbs of 40 W and 100 W. They are first connected in series and then in parallel across a source:

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40W bulb will be brighter in series and 100W in parallel

100W bulb will be brighter in series and 40W in parallel

40W bulb will be brighter in both the cares

100W bulb will be brighter in both the cares

Photoelectric effect and Compton effect prove the:

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Wave nature of light

Particle nature of light

Dual nature of light

Absolute zero is considered as that temperature at which:

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All liquids become gases

All gases become liquids

Water freezes

None of these

A church organ consist of open ended pipes ranging from 4m to 4 mm, if the speed ofsound is considered as 400 m/s then the min and max frequency is:

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400 Hz and 4 kHz

100 Hz and 100 kHz

50 Hz and 50kHz

400 Hz and 400 kHz

The mother and daughter elements with the emission of 𝖰 − 𝒓𝒂𝒚𝒔, are called:

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Isotopes

Isobars

Isomers

Isodiapheres

Hotness and coldness of an object is represented in terms of:

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Heat

Temperature

Chemicial

None of these

The unit of work function is

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eV

Volt

Farad

Herdz

Photo cells is a device which convert light into:

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Wave nature

Particle nature

Particle wave nature

Dual nature

A 100W, 220V bulb is operated on a 110V line, the power consumed is:

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25W

75W

50W

100W

Because of large mass when 𝑎 −paricle enters the atom or molecule it:

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Moves in zigzag path

Moves along straight line

Moves along circular path

None of these

When heat is added to the system, the entropy change is:

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Positive

Negative

Zero

None of these

When a dielectric is inserted between the plates of a capacitor, Which one is true

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Energy stored increase

Energy stored decrease

Capacitance decrease

All