If voltage applied on a capacitor is increased from V to 2V, choose the correct conclusion.

(a)

Q remains the same, C is doubled

(b)

Q is doubled, C doubled

(c)

C remains same, Q doubled

(d)

Both Q and C remain same

The electric field created by a _________ is basically a non-uniform electric field.

(a)

Test charge

(b)

Positive charge

(c)

Negative charge

(d)

Point charge

Which of the following cannot be the units of electric field intensity?

(a)

NC^-1

(b)

Vm^-1

(c)

JC^-1/m

(d)

JC^-1

A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. The equivalent resistance between its two diametrically opposite points, A and B as shown in the figure is
 

(a)

\(\pi \Omega\)

(b)

\(\frac{\pi}{2}\Omega\)

(c)

2\(\pi \Omega\)

(d)

\(\frac{\pi}{4}\Omega\)

Temperature co-effieient of resistance for metals is ______________.

(a)

constant

(b)

positive

(c)

zero

(d)

negative

When a current of 5 A flows through a conductor of resistance 3 \(\Omega \) the loss of power due to joule heating effect is_________

(a)

75 W

(b)

25 W

(c)

70.7 W

(d)

45 W

An electron moves in a straight line inside a charged parallel plate capacitor of uniform charge density σ. The time taken by the electron to cross the parallel plate capacitor undeflected when the plates of the capacitor are kept under constant magnetic field of induction  \((\vec{B})\) is

(a)

\({ \varepsilon }_{ ° }\frac { elB }{ \sigma } \)

(b)

\({ \varepsilon }_{ ° }\frac { lB }{ \sigma {l} } \)

(c)

\({ \varepsilon }_{ ° }\frac { lB }{ {e}\sigma } \)

(d)

\({ \varepsilon }_{ ° }\frac { lB }{ \sigma } \)

What is the current passing through a coil of radius of 8 cm having 50 turns, when a magnetic intensity at the centre of the coil is 125 A turns m^-1?

(a)

0.1 ampere

(b)

0.4 ampere

(c)

1 ampere

(d)

4 ampere

In an electrical circuit, R, L, C, and AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and current in the circuit is \(\frac{\pi}{3}\). Instead, if C is removed from the circuit, the phase difference is again \(\frac{\pi}{3}\). The power factor of the circuit is

(a)

1/2

(b)

1/\(\sqrt2\)

(c)

1

(d)

\(\sqrt3\)/2

Unit of inductive reactance is ___________

(a)

ohm-metre

(b)

mho-metre^-1

(c)

ohm

(d)

mho

Which of the following E.M waves has the longest wavelength?

(a)

Radio waves

(b)

IR

(c)

X-rays

(d)

visible

The radius of curvature of curved surface at a thin planoconvex lens is 10 cm and the refractive index is 1.5. If the plane surface is silvered, then the focal length will be, ______.

(a)

5 cm

(b)

10 cm

(c)

15 cm

(d)

20 cm

If an object moves towards a plane mirror with a speed V at an angle θ to the perpendicular to the plane of the mirror, find the relative velocity between the object and the image ____________.

(a)

V

(b)

2V

(c)

2 V cosθ

(d)

2 V sin θ

The wave associated with a moving particle of mass 3 x 10^–6 g has the same wavelength as an electron moving with a velocity 6 x 10⁶ ms^-1. The velocity of the particle is _____.

(a)

1.82 x 10^-18ms^-1

(b)

9 x 10^-2ms^-1

(c)

3 x 10^-31ms^-1

(d)

1.82 x 10^-15ms^-1

If the mean wavelength of light from sun is taken as 550 nm and its mean power as 3.8 x 10²⁶ W, then the number of photons emitted per second from the sun is of the order of _____.

(a)

10⁴⁵

(b)

10⁴²

(c)

10⁵⁴

(d)

10⁵¹

Photoelectric cells are used to control _______ of furnaces.

(a)

pressure

(b)

temperature

(c)

output power

(d)

input

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 charge of an alpha-particle is _______________

(a)

same as that of a proton

(b)

twice as that of an electron

(c)

thrice as that of an proton

(d)

twice as that of a neutron

A good _____ slows down neutrons by elastic collisions and it does not remove them by absorption.

(a)

fuel

(b)

moderator

(c)

coolant

(d)

control rod

Which of the following is not the advantage of PN junction diode over tube value?

(a)

Unlimited life

(b)

No warming-up time after switching

(c)

Large efficiency

(d)

Low consumption of power

The expression of Y in the following circuit is _______________.

(a)

AB + CD

(b)

A + BCD

(c)

A + B + C + D

(d)

A. B. C. D

If the distance between the conduction band and valence band is leV, then this combination is _______________.

(a)

semiconductor

(b)

metal

(c)

insulator

(d)

conductor

Large band width for higher data is achieved by using ________________.

(a)

Large bandwidth for higher data is achieved

(b)

high frequency audio wave

(c)

low frequency carrier wave

(d)

low frequency audio wave

FM broad cost is preferred over AM broadcast because _______________.

(a)

It is less noisy

(b)

reproduction is of much better quality

(c)

it is more noisy

(d)

both (a) & (b)

Optical fiber communication is generally preferred over general communication system because ____________.

(a)

it has signal security

(b)

it is more efficient

(c)

it cannot be jammed as easily as radio waves

(d)

all of the above