Explanation:
As the air inside the jar is pumped out, the air pressure decreases. Thus, the pressure in the liquid near the bottom of the beaker decreases.
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Hydrogen (H), deuterium (D), singly ionized helium (
and doubly ionized lithium (Li) all have one electron around the nucleus. Consider n =2 to n = 1 transition. The wavelengths of emitted radiations are 
and 
respectively. Then approximately
|
(a) |
(b) 4 |
|
(c) |
(d) |
Assertion : Interference pattern is made by using blue light instead of red light, the fringes becomes narrower.
Reason : In Young’s double slit experiment, fringe width is given by relation B = 
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite sides. Ratio of magnetic fields at these points will be
|
(a) 8 |
(b) 1/2 |
(c) 3 |
(d) 4 |
Light is an electromagnetic wave. Its speed in vacuum is given by the expression
|
(a) |
(b) |
(c) |
(d) |
A 10 μF capacitor is charged to a potential difference of 50 V and is connected to another uncharged capacitor in parallel. Now the common potential difference becomes 20 volt. The capacitance of second capacitor is
|
(a) 10 μF |
(b) 20 μF |
(c) 30 μF |
(d) 15 μF |
Electric field strength due to a point charge of 5μC at a distance of 80 cm from the charge is
|
(a) |
(b) 7 |
(c) 5 |
(d) 4 |
