Wave Optics — Physics STD 12 Science — Question

Which of the following relations is correct ?

A rectangular block of glass ABCD has a refractive index 1.6. A pin is placed midway on the face AB (Fig). When observed from the face AD, the pin shall:

A metallic sheet is inserted between the plates of a parallel plate capacitor. The capacitance of the capacitor(a) Increases(b) Is independent of the position of the sheet(c) Is maximum when the metal sheet in the middle(d) a, b

Which of the following does not fit into a group:

The x-component of the resultant of several vectors:

1. Is equal to the sum of the x-components of the vectors.
2. May be smaller than the sum of the magnitudes of the vectors.
3. May be greater than the sum of the magnitudes of the vectors.
4. May be equal to the sum of the magnitudes of the vectors.

A spherical surface of radius of curvature R separates air (refractive index 1.0) from glass (refractive index 1.5). The centre of curvature is in the glass. A point object P placed in air is found to have a real image Q in the glass. The line PQ cuts the surface at a point O, and PO = OQ. The distance PO is equal to (a) 5 R(b) 3 R(c) 2 R(d) 1.5 R

In order to increase the sensitivity of a moving coil galvanometer, one should decrease(a) The strength of its magnet(b) The torsional constant of its suspension (c) The number of turns in its coil   (d) The area of its coil

The capacitor of capacitance 4 μF  and 6 μF  are connected in series. A potential difference of  500 volts is applied to the outer plates of the two capacitor system. The potential difference across the plates of capacitor of 4 μF  capacitance is(a) 500 volts(b) 300 volts(c) 200 volts(d) 250 volts