Question # 1

In which of the following diodes when an electron combines with a hole during the forward biasing, photon of visible light is emitted.

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photo diode

light emitting diode

photo voltaic cell

all of them

Two sources of sound are said to be coherent if

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The produce sounds of equal intensity

They produce sounds of equal frequency

They produce sound waves vibrating with the same phase

They produce sound waves with zero or constant phase difference all instant of time

A the top of the trajectory of a projectile, the directions of its velocity and acceleration are

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Perpendicular to each other

Parallel to each other

Inclined to each other at an angle of 45°

Anitparallel to each other

The chemical behaviour of an atom is determined by

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binding energy

atomic number

mass number

number of isotopes

Physics details with the study of:

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Matter

Energy

Both of them

Human body

The work performed on an object does not depend on:

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Force applied

Angle at which force is inclined to the displacement

Initial velocity of the object

Displacement

When a shall explodes a mid-air, the total momentum of its fragments is

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less than the momentum of shell

equal to the momentum of shell

greater than the momentum of shell

none of them

In the equation E=mc² value of c is?

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186000 miles per hour

186000 miles per sec

3 X 10⁸m/sec

Both A and C

Both B and C

For a body executing S. H. M, its

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momentum remains constant

potential energy remains constant

kinetic energy remains constant

total energy remains constant

In the formula R = N x m for diffraction grating, N denotes:

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No. of lines/cm

No. of lines/meter

Total number of lines

None of above

Which one of the following waves belongs to electromagnetic spectrum

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Radio and TV waves

Radar waves

Micro waves

All of them

If the distance between two charges is doubled,the force between them will become:

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Double

Half

One third

One fourth

The substances whose resistance decreases with the increase in temperature these substances have coefficient of

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positive temperature

negative temperature

absolute temperature

zero temperature

The ideal gas law is

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P = nRT

V = nRT

PV =RT

PV =nRT

The maximum displacement of a body on either side of its equilibrium position is called

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frequency

amplitude

displacement

time period

In the doping process, the ratio of the doping atoms to the semi conductor atom is

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1 to 10

1 to 10³

1 to 10⁶

1 to 10⁹

The wave nature of light was proposed by:

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Newton

Thomas Young

Huygen

None of these

If a mass of 10 gm is suspended from a spring of k = 9.8 Nm^-1, then the extension will be:

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1 cm

1 m

10 mm

None of these

Triple point of water is

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273.16°F

372.16K

273.16°F

273.16

If volume of wire is 'AL' and there are 'n' numbers of charge carriers per unit volume, then the total number of charge carriers are

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n/AL

Al/n

nAL

nA/L

Graph of Black body radiation is example of

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Band spectra

Continuo's spectra

Line spectra

All

The intensity at a point due to a charge is inversely proportional to

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Amount of charge

Size of the charge

Distance between charge and the point

Square of the distance from the charge

None of these

The internal pressure of the blood is

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less than the external atmospheric pressure

greater than the external atmospheric pressure

equal to the external atmosphericpressure

none of them

The speed of randomly moving electrons depends upon

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pressure

volume

temperature

mass

Every crystalline solid has

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definite melting point

different melting points

may or may not be definite

none of them

One newton is a force that produces an acceleration of 0.5 m/sec²in a body of mass:

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2 kg

3 kg

4 kg

8 kg

An inertial frame is that frame in which

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a>0

a=0

a<0

none of these

The instantaneous acceleration of a body moving with constant speed in a circle:

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Remains constant

Is called centripetal acceleration

Tangential acceleration

None of these

If a given spring of spring constant K is cut into two identical segments, the spring constant of each segment is:

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K/2

2 K

4 K

None of these

The locus of all the points in the same phase of vibration is called:

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Wave packet

Wave front

Wave number

None of them

The SI unit of viscosity is

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kg m^-1s^-1

kg ms^-1

kg m^-1s^-2

kg m^-1s

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