A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10 divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1 volt, the resistance in ohms needed to be connected in series with the coil will be
|
(a) 99995 |
(b) 9995 |
(c) |
(d) |
(b) 9995
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The activity of a radioactive sample is 1.6 curie and its half-life is 2.5 days. Its activity after 10 days will be
|
(a) 0.8 curie |
(b) 0.4 curie |
(c) 0.1 curie |
(d) 0.16 curie |
An achromatic combination of lenses produces
|
(a) Coloured images |
|
(b) Highly enlarged image |
|
(c) Images in black and white |
|
(d) Images unaffected by variation of refractive index with wavelength |
A potentiometer consists of a wire of length 4 m and resistance 10Ω. It is connected to a cell of e.m.f. 2 V. The potential difference per unit length of the wire will be
|
(a) 0.5 V/m |
(b) 2 V/m |
(c) 5 V/m |
(d) 10 V/m |
A coil and a bulb are connected in series with a dc source, a soft iron core is then inserted in the coil. Then
|
(a) Intensity of the bulb remains the same |
(b) Intensity of the bulb decreases |
|
(c) Intensity of the bulb increases |
(d) The bulb ceases to glow |
Two conducting circular loops of radii 
and 
are placed in the same plane with their centres coinciding. If 
, the mutual inductance M between them will be directly proportional to
|
(a) |
(b) |
(c) |
(d) |
In a double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then in the interference pattern
|
(a) The intensities of both the maxima and the minima increase |
|
(b) The intensity of maxima increases and the minima has zero intensity |
|
(c) The intensity of maxima decreases and that of the minima increases |
|
(d) The intensity of maxima decreases and the minima has zero intensity |
A long straight wire carries a current of π amp. The magnetic field due to it will be 5 
at what distance from the wire [
permeability of air]
|
(a) |
(b) |
(c) |
(d) |
