Question # 1

Electric current is defined as:

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Flow of charges through conductor

Rate of flow of charges through conductor

Flow of electrons

Flow of protons

Brownian motion confirms the truth of :

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Wave theory of light

Boyle's law

Kinetic theory of gases

Adiabatic process

. Time rate of change of momentum is equal to

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Force

Impulse

Velocity

Both A and C

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

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Moving and point charges

Stationary and point charges

Moving and non-point charges

Stationary and large size charges

Electromagnetic waves emitted by hot bodies are called:

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Photoelectrons

Alpha rats

Thermal radiation

None of these

Number of spark plugs needed in diesel engine is:

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Four

Five

Six

None of these

Two bodies are projected at angle 𝜽 𝒂𝒏𝒅 (𝟗𝟎 − 𝜽) to the horizontal with the same speed. The ratio of their times of flight is:

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sin 𝜃 : 1

cos 𝜃 : 1

sin 𝜃 : cos𝜃

cos 𝜃 : sin𝜃

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:

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Zero at T

Greatest at T

) Greatest at P

the same at P as at T

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

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Continuous wave

Longitudinal wave

Pulse

Transverse wave

The maximum wavelength of a transverse wave that can be set up in a string of length Lis

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L

2L

V

4L

When a gas is compressed:

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Its internal energy decreases

Its temperature decreases

Its temperature increases

None of these

As in linear motion force determines linear acceleration where as in circular motion torque determines its

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Angular acceleration

Linear acceleration

Vibratory acceleration

Tangential acceleration

The energy of photon of wavelength 1240 nm is:

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0.5 eV

1.0 eV

1.5 eV

2.0 eV

In which process, the change in internal energy of the system of zero:

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Isochoric process

isobaric process

Adiabatic process

Isothermal process

Light elements do not emit X-rays because

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Electrons in it have high binding energy

These materials are non- material

There is a small difference in their energy shells

Electrons in it require very large energy to remove from these materials

Continuous spectrum of X-rays id due to an effect known as

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Photoelectric effect

Compton effect

Heisenberg effect

Bremsstrahlung

Which of the following does not have the same units:

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Work

Heat

Kinetic energy

Power

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

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

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Zero

n

2n

𝜋2

SI unit of kinetic energy of rotation is

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joule second

joule

joule second

joule meter

A piece of Aluminium (Al) and a piece of Germanium (Ge) are cooled T1 K to T2 K. The resistance of:

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Each of them increases

Each of them decreases

Al increases and Ge decreases

Al decreases and that of Ge increases

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

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25W

75W

50W

100W

Capacitance of a capacitor does not depend upon

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Separation between plates

Thickness of the plates

Area of the plates

Medium between the plates

The half-life of a certain element is 3.5 days at STP. If the temperature is doubled and pressure is reduced to half then half-life of the same element will be:

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1.75 days

3.5 days

7 days

14 days

Where in standing wave, do the vibrations of the medium occur?

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Only at the nodes

Only at the antinodes

At all points between the nodes

At all points between the antinodes

In a photocell, cesium coated oxidized silver emits electrons for :

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Visible light

Infrared light

Ultraviolet light

All of these

If the temperature difference between hot and cold body is greater the heat engine is:

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Not efficient

Less efficient

More efficient

NOne of above

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

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

Most motorbikes have ____________ cylinder/s engine but cars usually have _________ cylinders on the same crankshaft.

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Four , Six

One , four

two , five

None of these

A process in which no heat enters or leaves the system is called.

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Adiabatic process

Isothermal process

Isochoric process

None of these

select Which one of the following is not performing projectile motion

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A gas filled balloon

) Bullet fired from gun

A football kicked

A baseball shot

The ‘emf ’ is always even when no current is drawn through the battery of the cell:

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Zero

Present

Absent

Maximum

For a gas obeying Boyle's law, if the pressure is doubled the volume becomes:

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One half

Double

Four times

None of these

Ratio of dimension of K.E and power is:

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1:1

T:1

1:T

M:J

According to boyle's law, volume of a given mass of a gas is

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Inversely proportional mass at constant pressure

Directly proportional to pressure at constant temprerature

Inversely proportional pressure at constant temprature

None of these

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

Capacitor stores energy in the form of :

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Electric field

Both of these

Magnetic field

Gravitational field

A body of mass m tied to a string is moved in a vertical circle of radius r. the difference in tensions at the lowest point and the highest point is.

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2 mg

4 mg

6 𝑚g

8 mg

Between the plates of a parallel plate condenser there is 1mm thick paper of dielectric constant 4. Itis charged at 100 volt. The electric field in volt/meter between the plates of the capacitor is:

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100

25000

100000

400000

J.J Thomson finds:

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Particle nature of the electron

Dual nature of electron

Wave nature of electron

Electromagnetic nature of electron