Semiconductor Electronics: Materials, Devices and Simple Circuits — Physics STD 12 Science — Question

If in a nuclear fission, piece of uranium of mass 0.5 g is lost, the energy obtained in kWh is

(a) 1.25

(b) 2.25

(c) 3.25

(d) 0.25

A 1mm thick paper of dielectric constant 4 lies between the plates of a parallel-plate capacitor. It is charged to 100 volt the intensity of electric field between the plates of the condenser will be:

When a metallic rod falls freely, keeping its length horizontal and parallel to northsouth direction, emf induced across it is __________ .

A straight copper wire is moved in a uniform magnetic field such that it cuts the magnetic lines of force. Then

When cathode rays strike a metal target of high melting point with very high velocity, then

(a) X-rays are produced	(b) Ealpha-rays are produced
(c) TV waves are produced	(d) Ultrasonic waves are produced

A conducting rod PQ of length L = 1.0 m is moving with a uniform speed v = 2 m/s in a uniform magnetic field B = 4.0T  directed into the paper. A capacitor of capacity C = 10 mF is connected as shown in figure. Then

(a) qA = + 80 mC and qB = – 80 mC

(b) qA = – 80 mC and qB = + 80 mC

(c) qA = 0 = qB

(d) Charge stored in the capacitor increases exponentially with time

To obtain maximum EMF from a number of cells, they must be connected in.

Ray optics is valid when characteristic dimensions are:

The electronic transition from n = 2 to n = 1 will produce shortest wavelength in:

Electric flux per unit solid angle is defined as: