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

Magnetic field intensity at the centre of coil of 50 turns, radius 0.5 m and carrying a current of 2 A is

(a) 0.5

(b) 1.25

(c) 3

(d) 4

When a charge of 3 coulombs is placed in a uniform electric field, it experiences a force of 3000 Newton. Within this field, potential difference between two points separated by a distance of 1 cm is

(a) 10 volts

(b) 90 volts

(c) 1000 volts

(d) 3000 volts

An engine uses 30A of current. The resistance offered is 15 ohms. Calculate the power consumed by the engine in horse power.

In a cyclotron, a charged particle.

The figure indicates the energy level diagram of an atom and the origin of six spectral lines in emission (e.g. line no. 5 arises from the transition from level B to A). The following spectral lines will also occur in the absorption spectrum

(a) 1, 4, 6

(b) 4, 5, 6

(c) 1, 2, 3

(d) 1, 2, 3, 4, 5, 6

The plate characteristic curve of a diode in space charge limited region is as shown in the figure. The slope of curve at point P is 5.0 mA/V. The static plate resistance of diode will be

(a) 111.1W

(b) 222.2W

(c) 333.3W

(d) 444.4W

An electron jumps from the 4^th orbit to the 2^nd orbit of hydrogen atom. Given the Rydberg's constant  . The frequency in Hz of the emitted radiation will be

(a)

(b)

(c)

(d)

The work function of a metallic surface is 5.01 eV. The photo-electrons are emitted when light of wavelength 2000Å falls on it. The potential difference applied to stop the fastest photo-electrons is  [h = 4.14

(a) 1.2 volts

(b) 2.24 volts

(c) 3.6 volts

(d) 4.8 volts

In P-type semiconductor, there is

(a) An excess of one electron	(b) Absence of one electron
(c) A missing atom	(d) A donar level

What is the ratio of wavelength of radiations emitted when an electron in hydrogen atom jump from fourth orbit to second orbit and from third orbit to second orbit

(a) 27 : 25

(b) 20 : 27

(c) 20 : 25

(d) 25 : 27