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

The de-Broglie wavelength of a particle accelerated with 150 volt potential is  m. If it is accelerated by 600 volts p.d., its wavelength will be

(a) 0.25 Å

(b) 0.5 Å

(c) 1.5 Å

(d) 2 Å

When a thin mica sheet is placed between the plates of a condenser then the amount of charge, so compared to its previous value, on its plates will become:

A wall clock uses a vertical spring-mass system to measure the time. Each time the mass reaches an extreme position, the clock advances by a second. The clock gives correct time at the equator. If the clock is taken to the poles it will:

1. Run slow.
2. Run fast.
3. Stop working.
4. Give correct time.

Which of the following products in a hydrogen atom are independent of the principal quantum number n? The symbols have their usual meanings.

Electric potential of earth is taken to be zero because earth is a good

(a) Insulator

(b) Conductor

(c) Semiconductor

(d) Dielectric

Emf of a cell is:

Resistivity of a semiconductor depends on

(a) Shape of semiconductor

(b) Atomic nature of semiconductor

(c) Length of semiconductor

(d) Shape and atomic nature of semiconductor

Two positive point charges of 12 μC  and 8 μC  are 10cm apart. The work done in bringing them 4 cm closer is

(a) 5.8 J

(b) 5.8 eV

(c) 13 J

(d) 13 eV

The breakdown in a reverse biased p-n junction diode is more likely to occur due to.

What is the current (i) in the circuit as shown in figure

(a) 2 A

(b) 1.2 A

(c) 1 A

(d) 0.5 A