A thin conducting spherical shell of radius R has a charge Q which is uniformly distributed on its surface. The correct plot for electrostatic potential due to this spherical shell is _____.

(a)

(b)

(c)

(d)

The given figure is a plot of lines of force due to two charges q₁ & q₂ find out the sign of charges

(a)

both negative

(b)

both positive

(c)

upper positive and lower negative

(d)

upper negative and lower positive

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 the case of Wheatstone's Bridge the bridge balance condition will be obtained only when____

(a)

the current through the galvanometer is maximum

(b)

the current through the galvanometer is minimum

(c)

the current through the galvanometer is zero

(d)

the current through the galvanometer is infinity

Two short bar magnets have magnetic moments 1.20 Am² and 1.00 Am² respectively. They are kept on a horizontal table parallel to each other with their north poles pointing towards south. They have a common magnetic equator and are separated by a distance of 20.0 cm. The value of the resultant horizontal magnetic induction at the mid-point O of the line joining their centres is (Horizontal components of Earth’s magnetic induction is 3.6 × 10^–5 Wb m^–2 )

(a)

3.60 × 10^-5 Wb m^-2

(b)

3.5 × 10^-5 Wb m^-2

(c)

2.56 × 10^-4 Wb m^-2

(d)

2.2 × 10^-4 Wb m^-2

When the current flowing in a circular coil is doubled and the number of turns of the coil in it is halved, the magnetic field at its center will become _____________.

(a)

four times

(b)

same

(c)

half

(d)

double

The direction of force on a current carrying conductor placed in a magnetic field is given by _____

(a)

Fleming's Left Hand Rule

(b)

Fleming's Right Hand Rule

(c)

Ampere's velocity

(d)

Biot-Savart Law

In a series RL circuit, the resistance and inductive reactance are the same. Then the phase difference between the voltage and current in the circuit is

(a)

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

(b)

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

(c)

\(\frac{\pi}{6}\)

(d)

zero

An emf of 12V is induced when the current in the coil changes at the rate of 40 A S^-1. The coefficient of self induction of the coil is __________________.

(a)

0.3 H

(b)

0.003 H

(c)

30 H

(d)

4.8 H

The reactance of a capacitor is __________.

(a)

X_c = Cω

(b)

X_c = \(\frac{1}{Cω}\)

(c)

X_c = \(\frac{C}{ω}\)

(d)

X_c = \(\frac{ω}{C}\)

Which one of them is used to produce a propagating electromagnetic wave?

(a)

an accelerating charge

(b)

a charge moving at constant velocity

(c)

a stationary charge

(d)

an uncharged particle

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

The wavelength range of microwave is _______m

(a)

10^-8 to 0.35

(b)

10^-3 to 0.3

(c)

10^-8 to 10^-6

(d)

10^-3 to 10^-1

A point source of light B is placed at a distance L in front of the center of a mirror of width d hung vertically on a wall. A man walks in front of the mirror along a line parallel to the mirror at a distance of 2 L front it as shown. The greatest distance over which he can see the image of the light source in the mirror is ___________.

(a)

d/2

(b)

d

(c)

2d

(d)

3d

A diminished virtual image can be formed only in ______________.

(a)

Plane mirror parabolic mirror

(b)

A concave mirror

(c)

A convex mirror

(d)

concave

A concave mirror is used to focus the image of a flower on a nearby well 120 cm from the flower. If a lateral magnification of 16 is desired, the distance of the flower from the mirror should be _____________.

(a)

8 cm

(b)

12 cm

(c)

80 cm

(d)

120 cm

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

A charged oil drop is suspended in a uniform field of 3 x 10⁴ Vm^-1 so that it neither falls nor rises. The charge on the drop will be _____________.

(a)

3.3 x 10^-18C

(b)

3.2 x 10^-18C

(c)

1.6 x 10^-18C

(d)

4.8 x 10^-18C

The anode of a simple photo emissive cell is _______

(a)

glass tube

(b)

quartz crystal

(c)

platinum wire

(d)

iron rod

The clocks in moving ships will appear to go _______ clocks on earth.

(a)

faster than

(b)

slower than

(c)

the same as

(d)

stops after leaving earth

According to to Bohr, the relation between principal quantum number (n) and radius of the orbit (r) is _____________.

(a)

r α \(\frac1n\)

(b)

r α \(\frac{1}{n^2}\)

(c)

r α n

(d)

r α n²

A N-P-N transistor conducts when collector is _________ and emitter is ________ with respect to base.

(a)

positive, negative

(b)

positive, positive

(c)

negative, negative

(d)

negative, positive

The maximum carrier swing allowed in frequency modulation is ________________.

(a)

455 kHz

(b)

10.7 kHz

(c)

75 MHz

(d)

150 kHz

The alloys used for muscle wires in Robots are _____.

(a)

Shape memory alloys

(b)

Gold copper alloys

(c)

Gold silver alloys

(d)

Two dimensional alloys

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