Online Test

Question # 1

Max plank founded a mathematical model resulting in an equation that describes the shape of observed blackbody radiations curves exactly, in

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1890

1895

1900

1905

Using the relativistic result, the location of an aircraft after an hour's flight can be predicted to about

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20 m

30 m

50 m

57 m

In photoelectric effect the energy of ejected electron depends on

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The frequency

The intensity

Both frequency and intensity

None of these

By the fermentation of biomass using enzymes and by decomposition through bacterial action in the absence of air, we obtain

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Biogas

Ethanol

Benzene

None of these

The symbol for radian is

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rad

Rad

rd

rdn

An optical fibre with its protective case may be typically

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6 m

6 mm

6 cm

6 nm

When a body is subjected to some external force, deformation is produced in:

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Shape

Length

Volume

Any of these

None of these

A thin film is a transparent medium whose thickness with the wavelength of light are

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Not comparable

Comparable

Both

None of these

A mass spectrograph sort out

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molecules

atoms

elements

isotopes

Age of the Universe is

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5 × 10¹⁵ sec

5 × 10¹⁷ sec

5 × 10¹⁹ sec

None of these

For a fixed force, larger is the mass of a body, the

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greater is its acceleration

smaller is its acceleration

smaller is its weight

zero is its acceleration

Spokes used in a bicycle wheel increase its

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Moment arm

Moment of inertia

Acceleration

Velocity

The height at which the satellite stay directly above a particular point on the surface of the earth above the equator is

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24000 km

36000 km

42000 km

None of these

Which of the following have same SI units

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Force

Impulse

Momentum

B and C

In carbon colour coded resistance, the fourth Gold band indicates the tolerance is

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±5%

±10%

±20%

None of these

The velocity of sound in air depends on

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Frequency

Temperature

Amplitude

Pressure

A current-carrying straight conductor is placed in a magnetic field perpendicular to it. The force experienced by the conductor is

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F = 0

F = BIL Cosθ

F = BIL

F = BIL Sinθ

γ-rays like X-rays are electromagnetic waves which one is powerful

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X=-rays

γ-rays

Both are equal

None of these

Isotopes have same number of:

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Protons

Neutrons

Nucleons

Photons

When a silicon crystal is doped with a pentavalent element, then the atom of the pentavalent element is known as

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acceptor

donor

either of them

none of them

The entropy "S" of a system is defined by the relation

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ΔS = ΔQ/t

ΔS = ΔT/Q

ΔS = ΔQ/T

None of these

When pn-junction is reversed biased, the current flows through it is of the order of

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milli-amperes

amperes

nano-amperes

micro-amperes

Time dilation is the result of special theory of relativity in which

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Times increases

Time decreases

Remains the same

None of these

An object is placed at a distance of 200 cm from a convex lens of focal length 10 cm the linear magnification is

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1/3

2/3

3/4

None

If the vector sum of all the external forces acting on a body is zero, then the body will be in

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rotational equilibrium

translational

complete equilibrium

all of them

The range ofβ-particle is measured by the

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Effective depth of penetration

Length of erratic path

Unbroken lengths

None of these

β-particles are easily deflected by collisions than heavy

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α-particles

β-particles

γ-particles

none of these

Speed of theα-particle is

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~ 10⁵ms^-1

~ 10⁶ms^-1

~ 10⁷ms^-1

None of these

Electron was discovered by

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R.(A) Millikan

J.J. Thomson

W. Crooks

Einstein

__________ does not have linear strain

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Water

Copper

Aluminum

Iron

Light year is a unit of

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Distance

Speed

Acceleration

intensity

The temperature of the surface of sun is about

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5 million degree Celsius

10 million degree Celsius

15 million degree Celsius

20 million degree Celsius

An alternating current is converted into direct current by a

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dynamo

rectifier

transformer

motor

Light appears to travels in straight lines since

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It is not absorbed by the atmosphere

It is reflected by the atmosphere

Its wavelength is very small

Its velocity is very large

Angular displacement is a vector quantity for

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Small value of Δθ

Very small value of Δθ

All values of Δθ

None of these

An element with Z > 83 will decay

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by heating it

by applying external potential

naturally

none of them

In electronic quenching

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A gas is used

A positive voltage is used

A negative voltage is used

A large negative potential is used

When a dielectric material is introduced between the plates of a charged condenser the electric field between the plates

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Decreases

Increases

No change

May increase or decrease

The current in a light bulb rises to a maximum almost at the instant the bulb is turned on the current then decreases. this is because:

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Temperature of the filament rises

Resistance increases

Resistance decreases

Both (A) and (B)

Both (A) and (C)

The drag force F on a sphere of radius 'r' moving slowly with speed V through a fluid of viscosity η by Stake's law

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F = πηra

F = 6πηrω

F = 6πηrV

F = 6πηraV

When the difference between the frequencies of two tuning forks is 10, then

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we will hear 10 beats per second

we will hear 5 beats per second

we will hear 20 beats per second

it becomes difficult to recognize the beats