Explanation:
Frequency of a light wave, as it travels from one medium to another, always remains unchanged, while wavelength decreases.
Decrease in the wavelength of light entering a medium of refractive index $\mu$, is given by,
$\lambda_\text{M}=\frac{\lambda}{\mu},$
Where $\lambda_\text{M}$ = wavelength in medium
$\lambda$ = wavelength in vacuum
$\mu$ = refractive index
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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) |
A hollow conducting sphere of radius R has a charge (+Q) on its surface. What is the electric potential within the sphere at a distance r = 
from its centre
|
(a) Zero |
(b) |
(c) |
(d) |
The mass defect per nucleon is called
|
(a) Binding energy |
(b) Packing fraction |
(c) Ionisation energy |
(d) Excitation energy |
Semiconductor is damaged by the strong current due to
|
(a) Lack of free electron |
(b) Excess of electrons |
|
(c) Excess of proton |
(d) None of these |
A 4 mF condenser is charged to 400 V and then its plates are joined through a resistance. The heat produced in the resistance is
|
(a) 0.16 J |
(b) 0.32 J |
(c) 0.64 J |
(d) 1.28 J |
A radioactive material has an initial amount 16gm. After 120 days it reduces to 1gm, then the half-life of radioactive material is
|
(a) 60 days |
(b) 30 days |
(c) 40 days |
(d) 240 days |
