Explanation:
Velocity of a wave is given by:
$\text{v}=\frac{\text{E}}{\text{B}}$
Hence wave velocity change in both the cases.
Frequency of the wave remains the same.
Using $\text{v}=\text{f}\lambda,$ it can be concluded that both $\lambda_1$ and $\lambda_2$ are variable.
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Electric room radiator which operates at 225 volts has resistance of 50 ohms. Power of the radiator is approximately
|
(a) 100 W |
(b) 450 W |
(c) 750 W |
(d) 1000 W |
Two resistances 
and 
are joined as shown in the figure to two batteries of e.m.f. 
and 
. If is short-circuited, the current through is
|
(a) |
(b) |
(c) |
(d) |
The light when enters the human eye experiences most of the refraction while passing through
|
(a) Cornea |
(b) Aqueous humour |
(c) Vitrous humour |
(d) Crystalline lens |
A 10 
capacitor and a 20 capacitor are connected in series across a 200 V supply line. The charged capacitors are then disconnected from the line and reconnected with their positive plates together and negative plates together and no external voltage is applied. What is the potential difference across each capacitor
|
(a) |
(b) |
(c) 400 V |
(d) 200 V |
If the shift of wavelength of light emitted by a star is towards violet, then this shows that star is
|
(a) Stationary |
(b) Moving towards earth |
|
(c) Moving away from earth |
(d) Information is incomplete |
Assertion : The specific charge for positive rays is a characteristic constant.
Reason : The specific charge depends on charge and mass of positive ions present in positive rays.
|
(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. |
The dispersive power of the material of lens of focal length 20 cm is 0.08. The longitudinal chromatic aberration of the lens is
|
(a) 0.08 cm |
(b) 0.08/20 cm |
(c) 1.6 cm |
(d) 0.16 cm |
In Young's double slit experiment, if the widths of the slits are in the ratio 4 : 9, the ratio of the intensity at maxima to the intensity at minima will be
|
(a) 169 : 25 |
(b) 81 : 16 |
(c) 25 : 1 |
(d) 9 : 4 |
