Atoms — Physics STD 12 Science — Question

The kinetic energy of an electron is 5 eV. Calculate the de-Broglie wavelength associated with it (h = 6.6 × 10^–34 Js, m_e = 9.1 × 10^–31 kg)

(a) 5.47 Å

(b) 10.9 Å

(c) 2.7 Å

(d) None of these

The magnetic dipole moment of a current carrying coil does not depend upon:

Which among the following is the source of the magnetic field (magnetism)?

Displacement current is continuous:

Two infinite plane parallel sheets separated by a distance d have equal and opposite uniform charge densities σ. Electric field at a point between the sheets is

(a) Zero	(b)
(c)	(d) Depends upon the location of the point

There is a current of 1.344 amp in a copper wire whose area of cross-section normal to the length of the wire is 1 . If the number of free electrons per   is 8.4 , then the drift velocity would be

(a) 1.0 mm/sec

(b) 1.0 m/sec

(c) 0.1 mm/sec

(d) 0.01 mm/sec

An object 2.5 cm high is placed at a distance of 10 cm   from a concave mirror of radius of curvature 30 cm  The size of the image is

(a) 9.2 cm

(b) 10.5 cm

(c) 5.6 cm

(d) 7.5 cm

According to the Heisenberg uncertainty principle:

A silver voltameter of resistance 2 ohm and a 3 ohm resistor are connected in series across a cell. If a resistance of 2 ohm is connected in parallel with the voltameter, then the rate of deposition of silver

(a) Decreases by 25%	(b) Increases by 25%
(c) Increases by 37.5%	(d) Decreases by 37.5%