When current is passed in antimony-bismuth couple, then
|
(a) The junction becomes hot when the current is from bismuth to antimony |
|
(b) The junction becomes hot when current flows from antimony to bismuth |
|
(c) Both junctions become hot |
|
(d) Both junctions become cold |
(b) The junction becomes hot when current flows from antimony to bismuth
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A circular disc of which 2/3 part is coated with yellow and 1/3 part is with blue. It is rotated about its central axis with high velocity, then it will be seen as
|
(a) Green |
(b) Brown |
(c) White |
(d) Violet |
A thin oil layer floats on water. A ray of light making an angle of incidence of 40° shines on oil layer. The angle of refraction of light ray in water is (
)
|
(a) 36 .1° |
(b) 44.5° |
(c) 26. 8° |
(d) 28.9° |
A nucleus decays by 
emission followed by a gamma emission. If the atomic and mass numbers of the parent nucleus are Z and A respectively, the corresponding numbers for the daughter nucleus are respectively.
|
(a) Z - 1 and A - 1 |
(b) Z + 1 and A |
(c) Z - 1 and A |
(d) Z + 1 and A - 1 |
An electric heater of resistance 6 ohm is run for 10 minutes on a 120 volt line. The energy liberated in this period of time is
|
(a) 7.2 |
(b) 14.4 |
(c) 43.2 |
(d) 28.8 |
A physicist works in a laboratory where the magnetic field is 2 T. She wears a necklace enclosing area 0.01 m2 in such a way that the plane of the necklace is normal to the field and is having a resistance R = 0.01 Ω. Because of power failure, the field decays to 1 T in time 10–3 seconds. Then what is the total heat produced in her necklace ? (T = Tesla)
|
(a) 10 J |
(b) 20 J |
(c) 30 J |
(d) 40 J |
Potential gradient is defined as
|
(a) Fall of potential per unit length of the wire |
|
(b) Fall of potential per unit area of the wire |
|
(b) Fall of potential per unit area of the wire |
|
(d) Potential at any one end of the wire |
