Online Test

Question # 1

Amperean path is a:

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Closed path

Rectangular path

Circular path

Any of above

Broken path

In an n-p transistor circuit the collector current is 10 mA.If 90% of the electrons emitted reach the collector

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The emitter current will be 9mA

The emitter current will be 11mA

The base current will be 1mA

The base current will be 0.1mA

A proton,a electron and an α particle accelerated through the same potential difference enter a region of uniform magnetic field,moving at right angles to the magnetic field B.The ratio of their kinetic energies is:

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2 : 1 : 1

2 : 2 : 1

1 : 2 : 1

1 : 1 : 1

The value of young modulus in Nm^-2for water is

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70 x 10

2.2 x 10⁵

Zero

None of these

n-type germanium is obtained on doping intrinsic germanium with

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Phosphorus

Aluminium

Boron

Gold

The dot product of two vectors is negative when

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They are parallel vectors

They are anti-parallel vectors

They are perpendicular vectors

None of the above is correct

The Newton's formula for the speed of sound in air is corrected by

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Einstein

Rutherford

Planks

Laplace

The systolic blood pressure comes when

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Vessel collapse

Cutting off the blood flow

None of these

All of these

The superposition of the two waves of same frequency and amplitude travelling in the same direction gives rise to an effect called:

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Diffraction

Interference

Polarization

Dispersion

β-particles emitted with the

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Double energy

Same energy

Variable energy

None of these

How many radiations are coming out of a radioactive element

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α

β

α,

β

α, β, γ

Monochromatic light means the light having

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One color

Single wavelength

Single frequency

All of the above

A wire of a uniform cross-section A length L and resistance R is cut into two equal parts. The resistivity of each part will be:

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Doubled

Halved

Remains the same

One fourth

A train is moving away from a station at 25 m/s^-1and sounding a whistle of frequency 1000 Hz. What will be the apparent frequency as heard by an observer on the platform? (speed of sound 340 m/s^-1)

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1079.4 Hz

179.4 Hz

931.5 Hz

591.3 Hz

In which of the following components, pn-junction is used

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light emitting diode

photo diode

photo voltaic cell

all of them

Two boats moving parallel in a river

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Are pulled towards each other due to less pressure in between them

Get part due to increases in pressure in between them

Remain always parallel as there is no change in pressure

None of these

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

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isochoric process

isothermal process

adiabatic process

none of them

When boron is added as an impurity to silicon,the resulting material is.

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n type conductor

n type semiconductor

p-type conductor

p-type semiconductor

A particle performs simple harmonic motion of amplitude 0.020 m and frequency 2.5 Hz.What is its maximum speed?

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0.008 m s^-1

0.050 m s^-1

0.125 m s^-1

0.314 m s^-1

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

When a high energy photon interacts with a metal, which of the following effect is most likely to be taken place?

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pair production

photoelectric effect

Compton effect

none of them

Solar cell converts sunlight directly into

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potential energy

thermal energy

mechanical energy

electrical energy

Time period of simple pendulum is independent of

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Amplitude

Mass

Acceleration due to gravity

All of these

The speed of efflux is equal to the velocity gained by the falling fluid under the action of gravity through a certain height is known as

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Equation of continuity

Bernoulli s equation

Torrucelli s Theorem

Venturi s relation

As circular coil has 250 turns and a mean diameter of 20 cm. If carries a current of 5A. What is the strength of the magnetic field at a point on its axis at a distance of 5m from the centre of the coil ?

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4π × 10^-7 T

2π × 10^-7 T

2π × 10^-8 T

A rain drop of radius r falls from a certain height h above the ground. The work done by the gravitational force is proportional to

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r

r²

r³

r⁴

Ratio of longest and shortest wavelength of lyman series is:

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3/4

4/3

9/4

None

How many kinds of laser are there

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Solid only

Liquid only

Gaseous only

All of these

The apparatus used to compare the emf of two cells is

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Wheatstone bridge

potentiometer

ammeter

voltmeter

As the α-particle passes through matter, it losses its energy due to

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Excitation of atoms in elastic

Ionization of atoms

Collision

a and b

To wavelength of light by his experiment , Newton utilized:

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Wavelength of light

Intensity of light

amplitude wave

None of above

Two charges are placed a certain distance apart in air when a dielectric sheet is placed between them, the electro static force between them will

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Decrease

Increase

Remain unchanged

Become zero

If the mass of the uranium is much greater than the critical mass then

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More neutrons are produced

Rapid chain reaction

Huge explosion is produced

All of these

Two point charge +3μC and +8μC repel each other with a force of 40 N if a charge of -5μC us added to each of them then the force between them will become

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-10 N

+10 N

+20 N

-20 N

β-particles can be deflected by collisions than the α-particles is

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Difficult

Very easily

Easily

None of these

The S.I. units of magnetic field is

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Wb

Wb m^-1

Wb m^-2

None of these

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

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Double

Half

Three times

One fourth

One third

One kilogram of different substances contain

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same number of molecules

different number of molecules

may be same or different

none of them

The frequencies of X-rays,y-rays and ultraviolet rays are respectively a,b and c.Then

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a > b,b > c

a < b,b > c

a < b.b < c

a > b,b < c

A lift is moving downwards at a very high constant speed. A passenger present inside the lift standing on a weighing machine would notice that his weight

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is shown as zero on the scale

becomes zero

remains constant at a value less than this real weight

remains the same as his real weight

The conduction band in a solid

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may be empty

cannot be empty

should be filled

all of them