Online Test

Question # 1

A hollow metal sphere of radius 5 cm is change such that the potential on its surface 10 V. the potential at the centre of the sphere is

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Zero

10 volts

The same as that at a point 5 cm away from the surface

The same as that a at point 25 cm away from the surface

A particle is moving in a uniform magnetic field then

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Its momentum changes but total energy remains the same

Both momentum and total energy remains the same

Both changes

Total energy change but momentum remains

In common emitter amplifier (I₀/I_E) = 0.98,then current gain is

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49

4.9

98

9.8

A phenomenon in which a high energy photon scattered by an atomic electron and transfer a part of its energy is known as

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Photoelectric effect

Compton effect

X-rays

None of these

How many sivert can cause radiation burns to skin is

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1 SV

2 SV

3 SV

4 SV

Ultra-violet radiation of 6.2 eV falls on an aluminium surface.K.E of fastest electron emitted is (Work function = 4.2 eV)

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3.2 x 10-21 J

3.2 x 10-19 J

7 x 10-25 J

9 x 10-32 J

α-particle is

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Positively charge

Negatively charge

Neutral

None of these

The Zeroth law of thermodynamics states that

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a system remains at constant temperature if no heat is supplied to it

if two bodies are in thermal equilibrium with a third body then they must be in thermal equilibrium with each other

the heat supplied to a system is proportional to the internal energy of a system

there is no Zeroth law

Moment of inertia of a sphere is

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1/3 mr²

3/4 mr²

4/5 mr²

2/5 mr²

Proton was discovered by Rutherford in

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1915

1906

1910

1920

The field inside the solenoid is

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Weak

Strong

Very strong

None of these

The atom or molecules in crystalline solids are held together by:

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Cohesive force

Adhesive force

Gravitational force

Magnetic forces

The damping effect for the pith-ball due to air resistance and for the lead ball is

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Lowest

Greater

Much greater

None of these

If two non zero vectors A and B obey the relation |A + B| = |A - B|.then the angle between them is:

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120°

90°

60°

0°

Magnetic effect is utilized in

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Electric Iron

Thermocouple

Measurement of current

None of these

As cross-sectional area of the pipe decreases the speed of fluids must increase according to

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Bernoulli's equation

Venture's reaction

Equation of continuity

Torricelli's theorem

Two sources are said to be coherent if they have:

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Same amplitude

Same wavelength

Definite phase relation with each other

None of them

The symbol of ohm is

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C°

K

mol

Ω

The second law of thermodynamics is concerned with the situation in which

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Heat can be converted into work

Direction of flow of heat

Both A & B

None of these

The wavelength of microwaves is

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Smallest than the wavelength of violet light

Larger than the wavelength of red light

Smallest than the wavelength of yellow light

Larger than the wavelength of radio waves

When OP-AMP is used as inverting amplifier, which of the input terminal is grounded?

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inverting

non-inverting

any one of them

none of them

Which particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field?

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Li⁺

Electron

Proton

He⁺

The symbol for specific resistance of material of the wire is

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Ω

p

ω

t

Human body is composed of particles to produce electric force are

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Atoms

Molecules

Charges

All of them

The apparent size of an object depends on the angle subtended but it at the eye. As the angle increases the size of the object

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Smaller

Larger

Very large

None of these

Forα-particle and X-rays of equal absorbed dose, theα-particle are moer damaging than X-rays are

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10 times

20 times

30 times

40 times

The advantage/advantages of fiber optics than radio wave carriers

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Much wider band width

Capability

Immunity

All of these

Three particles having charges in the ratio of 1 : 2 : 3 produce the same point on the photographic film in the Thomson's experiment.Their masses are

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2 : 3 : 1

3 : 2 : 1

1 : 2 : 3

1 : 3 : 2

The speed of light in vacuum or in air is

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3 x 10¹⁰ m ! s

3 x 10⁹ m ! s

3 x 10⁸ m ! s

3 x 10⁷ m ! s

The K.E of the molecule of an ideal gas at absolute zero will be

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Infinite

Zero

Very high

Below zero

G. P. Thomson observed experimentally that electrons and neutrons possess

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particle-like properties

wave-like properties

neither particle nor wave-like properties

none of them

On moving from one place to another electromagnetic radiations behave as

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Particles

Waves

Both Particles and Waves

None of the above

In order to have constant current, a constant source is required as

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Current source

Potential difference

A resistance source

None of these

The direction of magnetic field as given by Fleming's rule for the solenoid is along

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Normal to the solenoid

Can't be taken

The axis of the solenoid

None of the above

The bridge circuit of full wave rectification uses

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one diode

two diodes

three diodes

four diodes

In an interference fringes pattern the fringes are

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Equally spaced

Wider near the centre and narrower away from it

Narrower near the centre and wider away from it

None of these

In electromagnetic induction, the induced current depends

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Conductor's speed of motion

Resistance of loop

Both a and b

None of these

For a given angle of projection if the time of flight of a projectile is doubled the horizontal range will increases to:

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Four times

Thrice

Once

Twice

The electrical circuit used to bet smooth DC output from a rectifier circuit is called

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Logic gates

Amplifier

Filter

Oscillator

Which of the following converts electrical energy into mechanical energy?

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D.C. generator

A.C. generator

motor

transformer

A mass spectrograph is the device use to

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Separate Isotopes

Find the isotopes

Find the neutrons

a and b