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

The electron emitted in beta radiation originates from:

Which of the following quantities do not change when a resistor connected to a battery is heated due to the current?

1. Drift speed.
2. Resistivity.
3. Resistance.
4. Number of free electrons.

Light waves travel in vaccum along the y-axis. Then the wave front is:

In a forward biased PN-junction diode, the potential barrier in the depletion region is of the form …       

(a)

(b)

(c)

(d)

The equivalent capacitance in the circuit between A and B will be

(a) 1 μF

(b) 2 μF

(c) 3 μF

(d)

The diode used in the circuit shown in the figure has a constant voltage drop of 0.5 V at all currents and a maximum power rating of 100 milliwatts. What should be the value of the resistor R, connected in series with the diode for obtaining maximum current

(a) 1.5 W

(b) 5 W

(c) 6.67 W

(d) 200 W

The mechanism of the hydrogen bomb is based on

(a) Fission of isotopes of hydrogen	(b) Fusion of protons
(c) Fusion of deutrium and tritium	(d) Fusion of neutrons

A caesium photocell, with a steady potential difference of 60V across, is illuminated by a bright point source of light 50 cm away. When the same light is placed 1m away the photoelectrons emitted from the cell

(a) Are one quarter as numerous

(b) Are half as numerous

(c) Each carry one quarter of their previous momentum

(d) Each carry one quarter of their previous energy

The X-ray wavelength of   line of platinum (Z=78) is 1.30   The X –ray wavelength of  line of Molybdenum (Z = 42) is

(a) 5.41Å

(b) 4.20Å

(c) 2.70Å

(d) 1.35 Å

Find out the value of current through 2Ω resistance for the given circuit

(a) 5 A

(b) 2 A

(c) Zero

(d) 4 A