A point positive charge is brought near an isolated conducting sphere (figure). The electric field is best given by

1

(a)

(b)

(c)

(d)

A capacitor of 4\(\mu\)F is connected as shown in the circuit. The internal resistance of the battery is 0.5\(\Omega \). The amount of charge on the capacitor plates will be

1

(a)

0

(b)

4 \(\mu\)C

(c)

1 6\(\mu\)C

(d)

8 \(\mu\)C

Two batteries of emf ε₁ and ε₂, (ε₂ >ε₁) and internal resistances r₁ and r₂ respectively are connected in parallel as shown in figure.

1

(a)

Two equivalent emf ε_eq of the two cells is between ε₁ and ε₂ i.e., ε₂ < ε_eq < ε₂

(b)

The equivalent emf ε_eq is smaller than ε₁

(c)

The ε_eq is given by εeq = ε₁ + ε₂ always

(d)

ε_eq is independent of internal resistances ε₁ and ε₂

There are two coils and B as shown in figure. A current starts flowing in B as shown, when A is moved towards B and stops when A stops moving. The current in A is counter clockwise. B is kept stationary when A moves. We can infer that

1

(a)

there is a constant current in the clockwise direction inA

(b)

there is a varying current in A

(c)

there is no current in A

(d)

there is a constant current in the counter clockwise direction in A

When a voltage measuring device is connected to AC mains, the meter shows the steady input voltage of 220 V. This means

1

(a)

input voltage cannot be AC voltage, but a DC voltage

(b)

maximum input voltage is 220 V

(c)

the meter reads not Ybut < V² > and is calibrated to read \(\sqrt{<{V}^{2}>}\)

(d)

the pointer of the meter is stuck by some mechanical defect

The direction of ray of light incident on a concave mirror is shown by PQ while directions in which the ray would travel after reflection is shown by four rays marked 1, 2, 3 and 4 (figure). Which of the four rays correctly shows the direction of reflected ray?

1

(a)

1

(b)

2

(c)

3

(d)

4

The wavelength of a photon needed to remove a proton from a nucleus which is bound to the nucleus with 1MeV energy is nearly

1

(a)

1.2 nm

(b)

1.2 x 10^-3 nm

(c)

1.2 x 10^-6nm

(d)

1.2 x 10 nm

The gravitational force between a H-atom and another particle' of mass m will be given by Newton's law \(F=G \frac{M m}{r^{2}}\), where r is in km

1

(a)

Gravitational mass of H-atom

(b)

Effective mass of H-atom

(c)

Nuclear mass of H-atom

(d)

Mass of electrons in H-atom

In a nuclear reactor, moderators slow down the neutrons which come out in a fission process. The moderator used have light nuclei. Heavy nuclei will not serve the purpose, because

1

(a)

they will break up

(b)

elastic collision of neutrons with heavy nuclei will not slow them down

(c)

the net weight of the reactor would be unbearably high

(d)

substances with heavy nuclei do not occur in liquid or gaseous state at room temperature

A 220 V AC supply is connected between points A and B (figure). What will be the potential difference V across the capacitor?

1

(a)

220 V

(b)

110 V

(c)

0 V

(d)

\(220 \sqrt{2} \mathrm{~V}\)