The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom, is
|
An electron of mass m with an initial velocity $\overrightarrow{V}= V_{o}\hat{i}\left(V_{o}>0\right)$ enters an electric field $\overrightarrow{E}= -E_{o}\hat{i}\left(E_{o}= constant >0 \right)$ at t=0 . If $\lambda_{o}$ is its de-Broglie wavelength initially, then its de-Broglie wavelength at time t is |
Answer |
|
For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is |
Answer |
|
When the light of frequency $2v_{o}$(where $v_{o}$ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is $v_{1}$. When the frequency of the incident radiation is increased to $5v_{o}$, the maximum velocity of electrons emitted from the same plate is $v_{2}$. The ratio of $v_{1}$ to $ v_{2}$ is |
Answer |
|
In the circuit shown in the figure, the input voltage $V_{i}$ is 20 V, $V_{BE}= 0$ and $V_{CE}= 0$. The values of $I_{B}, I_{C}$ and $\beta$ are given by |
Answer |
|
In a p-n junction diode, change in temperature due to heating |
Answer |
|
In the combination of the following gates the output Y can be written in terms of inputs A and B as |
Answer |
|
An em wave is propagating in a medium with a velocity $\overrightarrow{V}= V\hat{i}$. The instantaneous oscillating electric field of this em wave is along +y axis. Then the direction of oscillating magnetic field of the em wave will be along |
Answer |
|
The refractive index of the material of a prism is $\sqrt{2}$ and the angle of the prism is 30°. One of the two refracting surfaces of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is |
Answer |
|
An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm. If the object is displaced through a distance of 20 cm towards the mirror, the displacement of the image will be |
Answer |
|
The magnetic potential energy stored in a certain inductor is 25 mJ, when the current in the inductor is 60 mA. This inductor is of inductance |
Answer |
