Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

A plane electromagnetic wave with a single frequency moves in vacuum in the positive x direction. Its amplitude is uniform over the yz plane its wavelength:

If three bulbs 60W, 100W and 200W are connected in parallel, then(a) 200 W bulb will glow more(b) 60 W bulb will glow more(c) 100 W bulb will glow more(d) All the bulbs will glow equally

In the depletion region of a pn junction, there is a shortage of:

Assertion  :   The temperature coefficient of resistance is positive for metals and negative for p-type semiconductor.
Reason      : The effective charge carriers in metals are negatively charged whereas in p-type semiconductor they are positively charged.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

Why is the screen of the cathode ray tube coated ? Name the material used for coating:

An  object of length 6 cm is placed on the principle axis of a concave mirror of focal length f at a distance of 4f. The length of the image will be(a) 2 cm  (b) 12 cm(c) 4 cm(d) 1.2 cm

The square root of the product of inductance and capacitance has the dimension of(a) Length(b) Mass(c) Time  (d) No dimension

The self-inductance of a solenoid is L. Keeping the length and area same, the number of turns in the coil is increased to two times. The self-inductance of the solenoid will now be-

Polarised glass is used in sun glasses because(a) It reduces the light intensity to half an account of polarisation(b) It is fashionable(c) It has good colour(d) It is cheaper