The relative permittivity of water is _______.

(a)

ε_r = 70

(b)

ε_r = 75

(c)

ε_r = 80

(d)

ε_r = 85

The expression for electric field in vector form is

(a)

\(\frac { 1 }{ 4\pi { \varepsilon }_{ 0 } } \frac { q }{ r } \hat { r } \)

(b)

\(\frac { -1 }{ 4\pi { \varepsilon }_{ 0 } } \frac { q }{ r } \hat { r } \)

(c)

\(\frac { -1 }{ 4\pi { \varepsilon }_{ 0 } } \frac { q }{ r^2 } \hat { r } \)

(d)

\(\frac { 1 }{ 4\pi { \varepsilon }_{ 0 } } \frac { q }{ r^2 } \hat { r } \)

A condenser of 2μF capacitance is charged steadily from 0 to 5 coulomb. Which of the following graphs correctly represents the variation of potential difference across its plates with respect to the charge on the condensor [Q = C V ]

(a)

(b)

(c)

(d)

Which of the following has negative temperature coefficient of resistance?

(a)

copper

(b)

tungsten

(c)

carbon

(d)

silver

In an electrical arrangement as shown the equivalent resistance between X and Y will be

(a)

\(158.75\Omega \)

(b)

\(118.75\Omega \)

(c)

\(218.75\Omega \)

(d)

\(318.75\Omega \)

The most suitable metal for permanent magnet is ______________.

(a)

copper

(b)

aluminium

(c)

steel

(d)

iron

Cyclotron is used to _______________.

(a)

accelerate charged particles or ions to low voltages

(b)

decelerate charged particles or ions to high voltages

(c)

accelerate charged particles or ions to high energies

(d)

accelerate charged particles or ions to high voltages

The period of revolution of a charged particle inside a cyclotron does not depend on __________________.

(a)

the magnetic induction

(b)

the charge of the particle

(c)

the velocity of the particle

(d)

the mass of the particle

At the junction of an electric circuit the accumulation of charges is _______

(a)

positive maximum

(b)

negative maximum

(c)

zero

(d)

moderate

No current flows between two charged particles when connected if they have same ______

(a)

capcity

(b)

potential

(c)

charge

(d)

none of these

Transformer works on _____________.

(a)

AC only

(b)

DC only

(c)

both AC and DC

(d)

AC more effectively than DC

In a single phase dynamo, the direction of the induced current is given by __________

(a)

Faraday's laws

(b)

Maxwell's equations

(c)

Einstein's equation

(d)

Fleming's right hand rule

The voltage drop across the resistor in a LCR series circuit is __________________

(a)

V_R = IR

(b)

V_R = IR₂

(c)

V_R = I/R

(d)

V_R=R/I

Which of the following is a special aspect of EM wave?

(a)

can be deflected by electric field

(b)

can be deflected by magnetic filed

(c)

can be deflected by both electric & magnetic filed

(d)

none of these

A man is 180 cm tall and his eyes are 10 cm below the top of his head. In order to see his entire height right from toe to head, he uses a plane mirror kept at a distance of 1m from him. The minimum length of the plane mirror required is _____________.

(a)

180 cm

(b)

90 cm

(c)

85 cm

(d)

170 cm

Two plane mirrors are at right angles to each other. A man stands between them and combs hair with his right hand. In how many of the images will he be seen using his right-hand __________.

(a)

None

(b)

1

(c)

2

(d)

3

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

______ theory explains photo electric effect.

(a)

Electromagnetic

(b)

Quantum

(c)

Wave

(d)

Corpuscular

The minimum wavelength of X-rays produced in an X-ray tube at 1000 kV is ________________.

(a)

0.0124 Å

(b)

0.124 Å

(c)

1.24 Å

(d)

0.00124 Å

At 0 k temp, a N - type semi conductor ______________.

(a)

Does not haveany charge carriers

(b)

Has few holes but no free electrons

(c)

Few holes and few electrons

(d)

Has equal number of holes and electrons

The forbidden energy gap is largest in ______________.

(a)

conductor

(b)

metals

(c)

semiconductor

(d)

insulators

The device which is a combination of a receiver and a transmitter is ___________________.

(a)

Amplifier

(b)

Repeater

(c)

Transducer

(d)

Modulator

Resting frequency - 97 MHz. When modulated, it becomes 97.005 MHz. Find its carrier swing.

(a)

10 kHz

(b)

10 MHz

(c)

1MHz

(d)

50MHz

A geostationary satellite completes one revolution in________.

(a)

50 min

(b)

50 days

(c)

366 days

(d)

24 hours

Chinese scientists have created the world's first autonomous _________ to combat caner tumours.

(a)

RNA Robot

(b)

DNA Robot

(c)

m RNA Robot

(d)

r RNA Robot