A constant current i is passed through a resistor. Taking the temperature coefficient of resistance into account, indicate which of the plots shown in figure best represents the rate of production of thermal energy in the resistor
|
(a) a |
(b) b |
(c) c |
(d) d |
(d) d
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A light has amplitude A and angle between analyser and polariser is 60°. Light is reflected by analyser has amplitude
|
(a) A |
(b) A/ |
(c) |
(d) A/2 |
The tail of the comet is due to
|
(a) Vaporisation of water on the comet |
|
(b) Sublimation of vapour in the comet |
|
(c) Cooling of water in the comet |
|
(d) Vaporisation of heat in the comet |
In a potentiometer experiment the balancing with a cell is at length 240 cm. On shunting the cell with a resistance of 2 W, the balancing length becomes 120 cm. The internal resistance of the cell is
|
(a) 4 W |
(b) 2 W |
(c) 1 W |
(d) 0.5 W |
$\text{P}=\lim_\limits{\triangle\text{s}\rightarrow0}\frac{\text{F}}{\triangle\text{s}}$ and $\text{P}_1-\text{P}_2-\text{pgz}$
In an elevator accelerating upward.The angle of polarisation for any medium is 60o, what will be critical angle for this
(a)  
|
(b) 
|
(c) |
(d) |
If 10% of a radioactive material decays in 5 days, then the amount of original material left after 20 days is approximately
|
(a) 60% |
(b) 65% |
(c) 70% |
(d) 75% |
The focal lengths for violet, green and red light rays are 
and 
respectively. Which of the following is the true relationship
|
(a) |
(b) |
(c) |
(d) |
