Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

If the potential of a capacitor having capacity of 6 mF is increased from 10 V to 20 V, then increase in its energy will be

(a) 12 × 10–6 J

(b) 9 × 10–4 J

(c) 4 × 10–6 J

(d) 4 × 10–9 J

There is a uniform electric field of strength   along y-axis. A body of mass 1g and charge is projected into the field from origin along the positive x-axis with a velocity 10m/s. Its speed in m/s after 10s is (Neglect gravitation)

(a) 10

(b) 5

(c) 10

(d) 20

Mutual inductance of two coils is M. If current change in time t in first coil is I, then induced emf in the second coil is:

A battery of emf 10 V and internal resistance 3Ω is connected to a resistor as shown in the figure.  If the current in the circuit is 0.5 A.  then the resistance of the resistor will be

(a) 19 W

(b) 17 W

(c) 10 W

(d) 12 W

A person cannot see objects clearly beyond 2.0 m. The power of lens required to correct his vision will be

(a) + 2.0 D

(b) – 1.0 D

(c) + 1.0 D

(d) – 0.5 D

The potential difference applied to an X-ray tube is increased. As a result, in the emitted radiation:

1. The intensity increases.
2. The minimum wavelength increases.
3. The intensity remains unchanged.
4. The minimum wavelength decreases.

Which of the following statement is wrong

(a) Voltmeter should have high resistance

(b) Ammeter should have low resistance

(c) Ammeter is placed in parallel across the conductor in a circuit

(d) Voltmeter is placed in parallel across the conductor in a circuit

Two metal spheres of capacitance   and  carry some charges. They are put in contact and then separated. The final charges  and   on them will satisfy

(a)

(b)

(c)

(d)

The process of adding impurities to the pure semiconductor is called

(a) Drouping

(b) Drooping

(c) Doping

(d) None of these