A copper ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet while it is passing through the ring is
|
(a) Equal to that due to gravity |
|
(b) Less than that due to gravity |
|
(c) More than that due to gravity |
|
(d) Depends on the diameter of the ring and the length of the magnet |
(b) Less than that due to gravity
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A radioactive reaction is 
→ 
. How many α and β particles are emitted
|
(a) 10α, 6β |
(b) 4 protons, 8 neutrons |
|
(c) 6 electrons, 8 protons |
(d) 6β, 8α |
The decay constant λ of the radioactive sample is the probability of decay of an atom in unit time, then
|
(a) λ decreases as atoms become older |
|
(b) λ increases as the age of atoms increases |
|
(c) λ is independent of the age |
|
(d) Behaviour of λ with time depends on the nature of the activity |
Two coaxial solenoids 1 and 2 of the same length are set so that one is inside the other. The number of turns per unit length are 
and 
. The currents 
and 
are flowing in opposite directions. The magnetic field inside the inner coil is zero. This is possible when
|
(a) |
(b) |
|
(c) |
(d) |
100 cells each of e.m.f. 5 V and internal resistance 1 ohm are to be arranged so as to produce maximum current in a 25 ohms resistance. Each row is to contain equal number of cells. The number of rows should be
|
(a) 2 |
(b) 4 |
(c) 5 |
(d) 10 |
