Online Test

Question # 1

A body with frequency f would complete one vibration in

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F seconds

1/f seconds

1 seconds

1/T seconds

The points on a Huygen's wave front which sends out secondary wavelets are also

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Source

Source of secondary wavelets

Coherent sources of light

None of these

Shock absorber of a car is an example of

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Free oscillations

Forced oscillators

Damped oscillations

None of these

Mathematically the instantaneous velocity is defined as

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Glass and high carbon steel are the examples of

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brittle substances

ductile substances

plastic substances

elastic substances

When the source is moving away from the observer at rest the apparent frequency will be

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Increased

Decreased

Not changed

None of these

Radioactivity was discovered by Henri Becquerel in

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1880

1891

1893

1896

Which of the following material has longer half-life?

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radian

polonium

radium

uranium

Just before setting the sun may appear to be elliptical This happens due to

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Diffraction

Reflection

Dispersion

Refraction

The self inductance of a coil depends upon

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No. of turns of the coil

Area of cross-section of the coil

Material of the core

All of them

If the magnetic field is uniform, then the magnetic lines of forces are

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Curved

Parallel

Perpendicular

None of these

Two lenses of power +12 and -2 diopters are placed in contact the power of combination is

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10 diopters

8 diopters

6 diopters

12 diopters

In coordinate axes the right ward forces are taken as

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Positive

Negative

Just units only

None of these

Which phenomenon of light conclusively prove that light waves are transverse waves

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Reflection

Diffraction

Interference

Polarization

When resistance of a current carrying wire increases due to rise in temperature, the drift velocity of electrons:

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Decreases

Increases

Remains constant

Either of these

None of these

The amount of torque in D.C. motors depends upon

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current

resistance

electric field

force

Angular momentum has the same unit as

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Impulse x distance

Linear momentum x time

Work x frequency

Power x time

The original source of waves is

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Moon

Sun

Wind

None of these

Electromagnetic waves are

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Radio waves

Microwaves

Infra red waves

All of them

The locus of all points in a medium having same phase of vibration is called:

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Crest

Trough

Wavelength

Wavefront

The ionization potential of a hydrogen atom is 13.6 V.What will be the energy of the electron in the second orbit?

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-10.2 eV

-3.40 eV

-1.51 eV

-0.85 eV

Aquifier is a layer of rock holding water that allows water to percolate through it with

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Temperature

Pressure

Steams

None of these

At resonance if the capacitance of the capacitor is doubled in resonance series circuit than the resonance frequency is

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Also doubled

Become four times

Decreases by √2-times

Increases by √2 times

Speed of theβ-particle is

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~ .1 x 10¹⁰ms^-1

1 x 10⁸ms^-1

1 x 10⁹ms^-1

None of these

Paschen series lies in the region

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Ultraviolet

Infra-red

Visible

None of these

Strain is defined in terms of:

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Formation

Deformation

Area

Newtons

None of these

Unit of electric intensity is

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NC^-1

Vm^-1

Both A & B

None of these

When the object is closer to eye or near point, the image becomes

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Sharp

Clear visible

Blurred

None of these

If the three basic forces gravitational electrostatic and nuclear which two provide the attractive forces between two nucleons

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Electrostatic and nuclear

Electrostatic gravitational

Gravitational and nuclear

None of these

Solar cell converts sunlight directly into

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potential energy

thermal energy

mechanical energy

electrical energy

The typical wavelength of light source in transmitter is

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1.1 μm

1.2 μm

1.3 μm

1.4 μm

The resistivity of a class of elements below some critical temperature T falls to zero. The materials showing such property are called

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Semi conductors

Super-conductors

Insulators

Conductors

The energy needed to amplify and transmit the signals is provided by the satellite by

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Batteries

Generator

Solar cell panels

None of these

The basic circuit element in D.C. circuit is a resistor which controls the

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Capacitor

Voltage

Current

b and c

When the battery is connected at its ends, an electric field is set up at

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Its ends

Every point

Middle

All of them

Couple necessary to produce unit twist is

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Deflecting couple

Restoring couple

Torsion couple

None of these

In which case application of angular velocity is useful?

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When a body is rotating

When velocity of body is in a straight line

When velocity is in a straight line

None of these

Generator is a device which converts

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mechanical energy into electrical energy

kinetic energy into potential energy

chemical energy into mechanical energy

electrical energy into mechanical energy

The special theory of relativity is bases d on:

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Four postulates

Three postulates

Two postulates

One postulate

None of these

A pulse can be produced by a single disturbance in a medium from

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Rope

String

Coil spring

All of these

The electromagnetic waves has the property

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No medium

Rapidly propagation through medium

Velocity of light

All of them