- AParamagnetic substance.
- BFerromagnetic substance.
- CDiamagnetic substance.
- DNon magnetic substance.
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Which of the following (referred to a spherical mirror) do (does) not depend on whether the rays are paraxial or not?
In the Bohr model of the hydrogen atom, let R, v and E represent the radius of the orbit, the speed of electron and the total energy of the electron respectively. Which of the following quantity is proportional to the quantum number n
|
(a) R/E |
(b) E/v |
(c) RE |
(d) vR |
A nucleus of atomic mass A and atomic number Z emits β - particles. The atomic mass and atomic number of the resulting nucleus are
|
(a) A, Z |
(b) A + 1, Z |
(c) A, Z + 1 |
(d) A – 4, Z - 2 |
In the figure a capacitor is filled with dielectrics. The resultant capacitance is

|
(a) |
(b) |
(c) |
(d) None of these |
A fish rising vertically up towards the surface of water with speed 3 ms–1 observes a bird diving vertically down towards it with speed 9 ms–1. The actual velocity of bird is

|
(a) 4.5 ms–1 |
(b) 5. ms–1 |
(c) 3.0 ms–1 |
(d) 3.4 ms–1 |
A count rate meter shows a count of 240 per minute from a given radioactive source. One hour later the meter shows a count rate of 30 per minute. The half-life of the source is
|
(a) 120 min |
(b) 80 min |
(c) 30 min |
(d) 20 min |
Use of eddy currents is done in the following except
|
(a) Moving coil galvanometer |
(b) Electric brakes |
|
(c) Induction motor |
(d) Dynamo |