Explanation:
Iron is a ferromagnetic substance, so there are no magnetic lines of force inside it. So to protect the sensitive equipment from external magnetic field, it should be placed inside an iron can.
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The power of two convex lenses A and B are 8 diopters and 4 diopters respectively. If they are to be used as a simple microscope, the magnification of
|
(a) B will be greater than A |
(b) A will be greater than B |
|
(c) The information is incomplete |
(d) None of the above |
Two capacitors each of capacity 2 μF are connected in parallel. This system is connected in series with a third capacitor of 12 μF capacity. The equivalent capacity of the system will be
|
(a) 16 μF |
(b) 13 μF |
(c) 4 μF |
(d) 3 μF |
A force F acts between sodium and chlorine ions of salt (sodium chloride) when put 1 cm apart in air. The permittivity of air and dielectric constant of water are 
and K respectively. When a piece of salt is put in water electrical force acting between sodium and chlorine ions 1 cm apart is
|
(a) |
(b) |
(c) |
(d) |
