The relative permittivity of water is _______.

(a)

ε_r = 70

(b)

ε_r = 75

(c)

ε_r = 80

(d)

ε_r = 85

The electric potential V as a function of distance x (metres) is given by V = ( 5x² + 10x -9) volt. The value of electric field at a point x = 1m is __________

(a)

20 Vm^-1

(b)

6 Vm^-1

(c)

11 Vm^-1

(d)

-23 Vm^-1

The unit for electric susceptibility is

(a)

Nm² C^-2

(b)

C² N^-1 m^-2

(c)

C^-2Nm²

(d)

N^-1 m^-2C²

The capacitance of a parallel plate capacitor increases from 5μf of 50μf when a dielectric is filled between the plates. The permitivity of the dielectric is

(a)

8.854 x 10^-12 C²N^-1 m^-2

(b)

8.854 x 10^-11C²N^-1 m^-2

(c)

10 x 10^-12C²N^-1 m^-2

(d)

12 x 10^-12C²N^-1 m^-2

If the specific resistance of a potentiometer wire is 10^-7 Om and current flowing through it is 0.1 amp, cross-sectional area of wire is 10^-6 m², then potential gradient will be ________________.

(a)

10^-2 v/m

(b)

10^-4 v/m

(c)

10^-6 v/m

(d)

10^-8v/m

Electrical resistance is given by ___________________.

(a)

\(R=\cfrac { Al }{ \sigma } \)

(b)

\(R=\cfrac { l }{ \sigma A } \)

(c)

\(R=\cfrac { \sigma A }{ l } \)

(d)

\(R=\cfrac { \sigma }{ Al } \)

Joules's heating effect is desirable in ___________________.

(a)

AC dynamo

(b)

DC dynamo

(c)

water heater

(d)

transformer

The direction of the magnetic force on a positive charge moving in a magnetic field is given by ________________.

(a)

thumb rule

(b)

left hand rule

(c)

right hand rule

(d)

cork screw rule

Consider the motion of a charged particle in a uniform magnetic field directed into the paper. If velocity v of the particle is in the plane of the paper, the charged particle will describe a _____________.

(a)

straight line

(b)

circle

(c)

ellipse

(d)

hyperbola

The expression for water equivalent is _____________.

(a)

W = H (θ₂,θ₁)

(b)

W = \(\frac { { \theta }_{ 2 }-{ \theta }_{ 1 } }{ H } \)

(c)

both (a) and (b)

(d)

W = \(\frac { H }{ { \theta }_{ 2 }-{ \theta }_{ 1 } } \)

The magnetic declination for chennai is _______

(a)

-1° 5'

(b)

1°8'

(c)

-1°8'

(d)

1°5'

The force on a proton moving with a speed of 10⁵ m/s perpendicular to a magnetic field 10^-3 tesla is ______

(a)

1.6 x 10^-17 N

(b)

1.6 x 10^-27 N

(c)

1.6 x 10^-19 N

(d)

10^-2 N

Lenz's law is in accordance with the law of ________________.

(a)

conservation of charges

(b)

conservation of flux

(c)

conservation of momentum

(d)

conservation of energy

The self-inductance Lof a solenoid is given as _________________.

(a)

\(L=\frac { { \mu }_{ o }NA }{ l } \)

(b)

\(L=\frac { { \mu }_{ o }{ NA }^{ 2 } }{ l } \)

(c)

\(L=\frac { { \mu }_{ o }{ N }^{ 2 }A }{ l } \)

(d)

\(L=\frac { { { \mu }_{ o }A } }{ Nl } \)

The unit of impedance is ________________

(a)

mho-metre^-1

(b)

ohm

(c)

ohm-metre

(d)

mho-metre

The existence of E.M. waves was confirmed experimentally by __________________.

(a)

Hertz

(b)

Maxwell

(c)

Huygens

(d)

Planck

Accelerated charges would produce _____________.

(a)

sound waves

(b)

૪-rays

(c)

magnetic waves

(d)

electromagnetic waves

A pure red glass plate when placed in the path of the light absorbs everything except__________.

(a)

yellow

(b)

black

(c)

green

(d)

red

Band spectra are obtained from _________.

(a)

atoms

(b)

molecules

(c)

solids

(d)

semisolids

A man runs towards a mirror at a speed 15m/s. The speed of the image relative to the man is _______________.

(a)

15 ms^-1

(b)

30 ms^-1

(c)

35 ms^-1

(d)

20 ms^-1

When the intensity of a light source is increased?

(a)

the number of photons emitted by the source in unit time increases

(b)

more energetic photons are emitted

(c)

faster photons are emitted

(d)

total energy of the photons emitted per unit time decreases.

A photon of energy hv is absorbed by a free electrons of a metal having work function ф < hv _____________.

(a)

The electron is sure to come out

(b)

The electron is sure to come out with a kinetic energy ф < hv

(c)

Either the electron does not come out or it comes out with kinetic energy hv - ф

(d)

It may come out with a kinetic energy less than hv - ф

In the photoelectric phenomenon, if the ratio of the frequency of incident radiation incident on a photosensitive surface is 1: 2: 3, the ratio of the photoelectric current is _____________.

(a)

 1: 2 : 3

(b)

\(\sqrt { 1 } :\sqrt { 2 } :\sqrt { 3 } \)

(c)

1: 4 : 9

(d)

1: 1 : 1

When the momentum of a particle increases the de Broglie wavelength is ______________.

(a)

increases

(b)

decreases

(c)

does not change

(d)

infinity

The total energy of electrons in the ground state of a hydrogen atom is -13.6 eV. The k.E of an electron in the first excited state is ____________.

(a)

6.8 eV

(b)

13.6 eV

(c)

1.7 eV

(d)

3.4 eV

An a-particle of energy 10 meV is scattered through 180^o by a fixed uranium nucleus. The distance of the closest approach is of the order of _____________.

(a)

1Å

(b)

10^-10 cm

(c)

10^-12 cm

(d)

10^-15 cm

The intrinsic semi-conductor has ______________.

(a)

A finite resistance which does not change with temperature

(b)

Infinite resistance which decreases with temperature

(c)

Finite resistance which decreases with temperature

(d)

Finite resistance which does not change with temperature

In the Ge sample, traces, of gallium is added as an impurity. The resultant sample would behave like_____________.

(a)

a conductor

(b)

a p -type semiconductor

(c)

an N - type semiconductor

(d)

an insulator

In semiconductors at a room temperature ________________.

(a)

the valence band is partially empty and the conduction band is partially filled

(b)

the valence band is completely filled

(c)

the valence band is completely filled and the conduction band is partially filled

(d)

the conduction band is completely empty

The process of increasing the strength of a signal using an electric circuit is called ________________.

(a)

amplification

(b)

modulation

(c)

demodulation

(d)

transmission

In modulation process radio frequency wave is termed as ______________.

(a)

modulated wave

(b)

modulating wave

(c)

carrier wave

(d)

none

The size of the Nano robots is reduced to ________ level to perform a task in very small space.

(a)

Macroscopic

(b)

Robots DNA

(c)

Microscopic

(d)

Bacteria