Wave Optics — Physics STD 12 Science — Question

Dynamo is a device for converting

(a) Electrical energy into mechanical energy

(b) Mechanical energy into electrical energy

(c) Chemical energy into mechanical energy

(d) Mechanical energy into chemical energy

Which one of the following gives the resultant capacitor when capacitors are joined in series?

Q value for neutron decay is:

A magnet is made to oscillate with a particular frequency, passing through a coil as shown in figure. The time variation of the magnitude of e.m.f. generated across the coil during one cycle is

(a)	(b)
(c)	(d)

A parallel plate condenser is immersed in an oil of dielectric constant 2. The field between the plates is

(a) Increased proportional to 2	(b) Decreased proportional to
(c) Increased proportional to	(d) Decreased proportional to

Biological importance of Ozone layer is 

(a) It stops ultraviolet rays

(b) Ozone rays reduce green house effect

(c) Ozone layer reflects radio waves

(d) Ozone layer controls   radio in atmosphere

In the network shown in the figure, each of the resistance is equal to 2Ω. The resistance between the points A and B is

(a) 1 Ω

(b) 4 Ω

(c) 3 Ω

(d) 2 Ω

Pure inductance of 3.0 H is connected as shown below. The equivalent inductance of the circuit is

(a) 1 H

(b) 2 H

(c) 3 H

(d) 9 H

In the given figure, the electron enters into the magnetic field. It deflects in ...... direction

(a) + ve X direction

(b) – ve X direction

(c) + ve Y direction

(d) – ve Y direction