Online Test

Question # 1

If red light is incident on sea water it appears

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Red

Green

Blue

Yellow

The magnetic lines of force like electric lines of force

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Are closed

Are not closed

Are open

Are not open

The nature of radiations emitted by a hot body depend upon its:

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Meterial

Temperatutre

Colour

Volume

Length

The optical fibre is covered for protection with

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rubber jacket

plastic jacket

steel jacket

copper jacket

According o Einsteins theory space time is

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Just coordinates

A straight line

Curved

None of these

A heat engine converts thermal energy to mechanical work which is

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All

Partly

Some

None of these

The discharge tube of the - Ne laser is filled with

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He 80 % ; Ne 20 %

He 85; Ne 15 %

He 90 %; Ne 10 %

None of these

In sound waves during compression

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Density medium is maximum

Pressure of medium is maximum

Density of medium is minimum

Both A and B

The speed of sound

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Increases with the increase of the gas pressure

is not affected with the change in the gas pressure

decreases with the increase of the gas pressure

none of them

Electrons are

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positively charged

negatively charged

masslesss

neutral

The crest is a pattern in which the rope is displaced

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Below its equilibrium position

Above its equilibrium position

Above and below its equilibrium position

None of these

Consider the following statement about dimensions

P: Force = Acceleration due to gravity x Mass

Q: Electric charge = Current x Time

R: Magnetic flux = Electric voltage x Time

The correct statements are:

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R, P only

P, Q only

Q, R only

P, Q and R

Energy can be stored in

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Magnetic field of a capacitor

Electric field of a capacitor

Dielectric

None of these

The mechanical waves are generated by

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In ropes

Coil of springs

Water waves

All of these

In a straight current-carrying conductor, the direction of magnetic field can be found by

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right hand rule

left hand rule

head to tall rule

none of them

Indirectly heated cathode means:

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Cathode heats the filament

Grid heats the filament

Filament heats the cathode

Both A & B

A thermister is a

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Heat temperature resistor

Current sensitive resistor

Voltage sensitive resistor

None of these

In inductive circuit V leads I by

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π

π/2

2π

In phase

A body of mass 3 kg lies on the surface of the table 2 m high It is moved on the surface by 4 m The change of P.E will be

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Zero

9.8 j

19.6 j

329 j

The current through a metallic conductor is due to the motion of:

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Electrons

Protons

Neutrons

Free electrons

A bar magnet is equivalent to

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Toroid carrying current

Straight conductor carrying current

Solenoid carrying current

Circular coil carrying current

The ionizing ability of β-particles is less then the α-particle about

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100 times less

150 times less

200 times less

None of these

Turn table is the plateform over which we place

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Diffraction grating

Prism

Glass slab

a and b

Calculate entropy change when 1.0 Kg ice at 0^oC melts into water at 0^oC. Latent heat of fusion of ice L_f = 3.36 × 10⁵ J Kg^-1

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1.18 × 10² JK^-1

1.20 × 10⁴ J Kg^-1

1.23 × 10³ JK^-1

1.23 × 10⁴ J Kg^-1

Solid state detector are used in_______ mode.

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Forward bias

Reverse bias

Without bias

In sun light

The source in the heat engine is at

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Low temperature

High temperature

Zero temperature

None of these

The electric field was discovered

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Michel Faraday

Oersted

Newton

Ampere

Which does not show polarization

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Longitudinal wave in gas

Transverse wave in gas

Both a and b

None of these

When n-type of semiconductor is heated.

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Number of electrons increases while that of holes decreases

Number of holes increases while that of electrons decreases

Number of electrons and holes remains same

Number of electrons and holes increases equally.

The blood pressure of the person

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Decreases with age

Increases with age

Remains the same

None

Blood is an/a

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Ideal fluid

Perfect fluid

Compressible fluid

Incompressible fluid

According to relation S = rθ, then θ in simple pendulum is

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gX/I

X/I

g/I

I/g

In the Wilson's cloud chamberα- andβ- particles are detected. What is seen in the chamber whenα-particles are let into the chamber?

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long straggly paths

long continuous straight trials

short continuous straight trails

short straggly paths

If rope of lift breaks suddenly,The tension exerted by the surface of lift is (a = Acceleration of lift)

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mg

m (g + a)

m (g - a)

0

Young's modulus for water is

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0

2

5

9

Which of the following is true?

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Neither momentum nor kinetic energy is conserved in inelastic collisions

Momentum is conserved in all collisions only in inelastic collisions

Momentum is conserved in all collisions but not kinetic energy

Both momentum and kinetic energy are conserved in all collisions

The concept of direction is purely:

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Absolute

Relative

Relative to stars always

Relative to the sun always

None of these

A driver in a lake wants to signal his distress to a person sitting on the edge of the lake flashing his water proof torch He should direct the beam

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Vertically up wards

Horizontally

At angle to the vertical which is slightly less than the critical angle

At an angle to the vertical which is slightly more than critical angle

Wave front is the locus or all points in vibration are in the same

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Frequency

Phase

Wavelength

All of these

If a charge Q is dispersed over tow spheres of radii R and r such that their surface charge densities are equal. What is the ratio of the charges on the spheres?

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2r/R

R²_/r²

R³/5R³

R⁴/R⁴

Under feeble driving force, the amplitude of the motion may become

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Very small

Large

Extra large

Extra ordinarily large