Two identical point charges of magnitude –q are fixed as shown in the figure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement?

(a)

A₁ and A₂

(b)

B₁ and B₂

(c)

both directions

(d)

No stable

An electric dipole is placed at an alignment angle of 30^o with an electric field of 2 x 10⁵ NC^-1. It experiences a torque equal to 8 N m. The charge on the dipole if the dipole length is 1 cm is

(a)

4 mC

(b)

8 mC

(c)

5 mC

(d)

7 mC

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric flux through each Gaussian surface in increasing order.

(a)

D < C < B < A

(b)

A < B = C < D

(c)

C < A = B < D

(d)

D > C > B > A

Rank the electrostatic potential energies for the given system of charges in increasing order

(a)

1 = 4 < 2 < 3

(b)

2 = 4 < 3 < 1

(c)

2 = 3 < 1 < 4

(d)

3 < 1 < 2 < 4

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

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

(a)

Capacitance

(b)

Charge

(c)

Voltage

(d)

Energy density

The force experienced by a unit charge is called ____________

(a)

Electric potential

(b)

Electric flux

(c)

Electric field

(d)

Static electricity

A condenser is charged to a potential of 200V and has a charge of 0.1C. The energy stored in it is _____________

(a)

1 J

(b)

2 J

(c)

10 J

(d)

20 J

Increasing the charge on the plates of a capacitor means ___________

(a)

increasing the capacitance

(b)

increasing the potential difference between the plates

(c)

both (a) and (b) above

(d)

none of the above

A non-conducting material which has no free electrons is called

(a)

capacitor

(b)

Dielectric

(c)

conductor

(d)

Inductor

When 4V emf is applied across a 1F capacitor, it will store energy of

(a)

2J

(b)

4J

(c)

6J

(d)

8J

Value of k in Coulomb's law depends upon

(a)

magnitude of charges

(b)

distance between charges

(c)

both (a) and (b)

(d)

medium between two charges

A charge Q is placed at the corner of a cube. The electric flux through all the six faces of the cube is

(a)

\(\frac { Q }{ { 3\varepsilon }_{ 0 } } \)

(b)

\(\frac { Q }{ { 6\varepsilon }_{ 0 } } \)

(c)

\(\frac { Q }{ { 8\varepsilon }_{ 0 } } \)

(d)

\(\frac { Q }{ { \varepsilon }_{ 0 } } \)

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)

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

A wire connected to a power supply of 230 V has power dissipation P₁. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case power dissipation is P₂. The ratio \(\frac{P_2}{P_1}\) is ______.

(a)

1

(b)

2

(c)

3

(d)

4

In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in USA. If the resistance of a 60 W bulb for use in India is R, the resistance of a 60 W bulb for use in USA will be ______.

(a)

R

(b)

2R

(c)

\(\frac{R}{4}\)

(d)

\(\frac{R}{2}\)

Emission of electrons by the absorption of heat energy is called ______ emission.

(a)

photoelectric

(b)

field

(c)

thermionic

(d)

secondary

Find the energy released when 5.5 g of matter is used.

(a)

1.6 x 10⁸ J

(b)

49.5 x 10¹⁵ J

(c)

49.5 x 10¹⁵ J

(d)

1.6 x 10¹⁹J

Atomic number of H-like atom with ionization potential 122.4 V for n = 1 is _____.

(a)

1

(b)

2

(c)

3

(d)

4

Millikan's oil drop experiment established that is ____________.

(a)

electric charge depends on velocity

(b)

electric charge is quantised

(c)

electron has wave nature

(d)

electron has particle nature

A beam of electron posses undeflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off and the same magnetic field is maintained, the electrons move ______________.

(a)

in a circular orbit

(b)

along a parabolic path

(c)

along a straight line

(d)

in an elliptical orbit

When an electric field is applied to an atom each of the spectral lines split into several lines. This effect is known as ________________.

(a)

Zeeman effect

(b)

Stark effect

(c)

Raman effect

(d)

Seebeck effect

J.J. Thomson discovered ________

(a)

protons

(b)

neutrons

(c)

electrons

(d)

quarks

A spray of fine droplets of a highly viscous liquid could be, accomplished by a _________

(a)

filter

(b)

steve

(c)

atomizer

(d)

mixer

When the electron jumps from any of the outer orbits to the first orbit, spectral lines are emitted in the ________ region.

(a)

visible

(b)

IR

(c)

X-ray

(d)

UV

In gamma ray emission from nucli _____________.

(a)

both the neutron number and the proton number change

(b)

there is no change in neutron number and the proton number change

(c)

only the neutron number changes

(d)

only the proton number changes

In the nuclear reaction ₄Be⁹ + X ➝ ₆C¹² + ₀n¹ X stands for ______________.

(a)

proton

(b)

α particle

(c)

electron

(d)

deutron

Minimum size of a system in which at least 1 neutron is available for further fission is called __________

(a)

cut-off size

(b)

critical size

(c)

range of reactor

(d)

capability criteria

The moderator used in nuclear reactor is ________________.

(a)

Cadmium

(b)

Boron oxide

(c)

Heavy water

(d)

Uranium

The blue print for making ultra durable synthetic material is mimicked from _____.

(a)

Lotus leaf

(b)

Morpho butterfly

(c)

Parrot fish

(d)

Peacock feather

The method of making nanomaterial by assembling the atoms is called _____.

(a)

Top down approach

(b)

Bottom up approach

(c)

Cross down approach

(d)

Diagonal approach

Best example for applications of nanotechnology is ______________.

(a)

Chemical industry

(b)

Engineering

(c)

medicine

(d)

all of these

One of the of Young’s double slits is covered with a glass plate as shown in figure. The position of central maximum will,_____.

(a)

get shifted downwards

(b)

get shifted upwards

(c)

will remain the same

(d)

data insufficient to conclude

A rear mirror of a vehicle is cylindrical having a radius of curvature of 10 cm. The length of the arc of the curved surface is also 10 cm. If the eye of the driver is assumed to be at a large distance, from the mirror, then the field of view in radian is ____________.

(a)

0.5

(b)

1

(c)

2

(d)

4

The variation of frequency of carrier wave with respect to the amplitude of the modulating signal is called ______.

(a)

Amplitude modulation

(b)

Frequency modulation

(c)

Phase modulation

(d)

Pulse width modulation

The Ac current gain of a transistor is 100. If the base current changes by 100 μA. What is the charge in the collector current ______.

(a)

20 mA

(b)

30 mA

(c)

10 mA

(d)

10 μA

The input resistance is ________

(a)

1k Ω

(b)

10 Ω

(c)

10 k Ω

(d)

100 Ω

In frequency modulation _____________.

(a)

the amplitude of modulated wave varies as frequency

(b)

the frequency of modulated wave varies as amplitute the frequency

(c)

the amplitude of modulated wave varies as amplitute of carrier wave

(d)

the frequency of modulated wave varies as frequency of modulating wave

Broadcasting antennas are generally ______________.

(a)

unidirectional

(b)

vertical

(c)

horizontal

(d)

none

Long distance radio communication employs _______ wave propagation.

(a)

ground

(b)

sky

(c)

space

(d)

surface

Low efficiency and small operating range are features of _________ type of transmission.

(a)

PM

(b)

AM

(c)

PCM

(d)

FM

The centre of frequency is extremely stable in ___________ modulated wave.

(a)

amplitude

(b)

frequency

(c)

phase

(d)

pulse-code

The speaker converts ________ energy into ______ energy.

(a)

electrical, sound

(b)

sound, electrical

(c)

light, sound

(d)

sound, mechanica

The circuit in which an inductor and a capacitor are connected in parallel is called as a _________

(a)

tank

(b)

series

(c)

inductor

(d)

capacitor

________ wire is used between telephones and the central office

(a)

Flat

(b)

Multiconnector

(c)

Co-axial

(d)

Twisted pair

The distance of a geostationary satellite's orbit from the Earth is about _______

(a)

366 km

(b)

108 km

(c)

36 x 10³km

(d)

30 m

Supplier of majority charge carriers in a transistor is ______

(a)

emitter

(b)

base

(c)

collector

(d)

resistor

Acceptor of majority charge carriers in a transistor is ___________

(a)

emitter

(b)

base

(c)

collector

(d)

resistor.

Input characteristics of an NPN transistor in (CE mode) is drawn between ________

(a)

I_B and V_BE

(b)

V_BE and V_CE

(c)

V_CC and V_EE

(d)

V_B and I_E

Output characteristics of an NPN, transistor in CE mode is drawn between ___________

(a)

I_C and V_BE

(b)

I_E and V_CE

(c)

I_B and V_CE

(d)

I_C and V_CE