List of top Physics Questions

Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter 0.1 $\mu$m. If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that:

A galaxy is moving away from the earth at a speed of 286 kms$^{-1}$. The shift in the wavelength of a redline at 630 nm is x $\times 10^{-10}$ m. The value of x, to the nearest integer, is ________. [Take the value of speed of light c, as 3 $\times 10^8$ ms$^{-1}$]

An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 Lumens. Now, if the analyzer is rotated around the horizontal axis (direction of light) by 30° in clockwise direction, the intensity of emerging light will be ________ Lumens.

In Young's double slit experiment, if the source of light changes from orange to blue then:

In the Young's double slit experiment, the distance between the slits varies in time as $d(t) = d_0 + a_0 \sin \omega t$; where $d_0, \omega$ and $a_0$ are constants. The difference between the largest fringe width and the smallest fringe width obtained over time is given as :

The difference in the number of waves when yellow light propagates through air and vacuum columns of the same thickness is one. The thickness of the air column is ________ mm.
[Refractive index of air = 1.0003, wavelength of yellow light in vacuum = 6000 Å]

Two coherent light sources having intensity in the ratio $2x$ produce an interference pattern. The ratio $(I_{max} - I_{min}) / (I_{max} + I_{min})$ will be :

Four NOR gates are connected as shown in figure. The truth table for the given figure is :

For the given circuit, the power across zener diode is __________ mW.

Identify the logic operation carried out by the given circuit :

Statement I : By doping silicon semiconductor with pentavalent material, the electrons density increases.
Statement II : The n-type semiconductor has net negative charge.
In the light of the above statements, choose the most appropriate answer from the options given below :

For a transistor in CE mode to be used as an amplifier, it must be operated in :

A circuit is arranged as shown in figure. The output voltage $V_o$ is equal to ________ V.

For a transistor $\alpha$ and $\beta$ are given as $\alpha = \frac{I_C}{I_E}$ and $\beta = \frac{I_C}{I_B}$. Then the correct relation between $\alpha$ and $\beta$ will be :

A zener diode of power rating 2 W is to be used as a voltage regulator. If the zener diode has a breakdown of 10 V and it has to regulate voltage fluctuated between 6 V and 14 V, the value of R$_S$ for safe operation should be _________ $\Omega$.

Choose the correct waveform that can represent the voltage across R of the following circuit, assuming the diode is ideal one :

If $V_A$ and $V_B$ are the input voltages (either 5 V or 0 V) and $V_o$ is the output voltage then the two gates represented in the following circuits (A) and (B) are :
\begin{center} \includegraphics[width=0.5\textwidth]{logic_gates} \end{center}

Statement I : To get a steady dc output from the pulsating voltage received from a full wave rectifier we can connect a capacitor across the output parallel to the load $R_L$.
Statement II : To get a steady dc output from the pulsating voltage received from a full wave rectifier we can connect an inductor in series with $R_L$.
In the light of the above statements, choose the most appropriate answer from the options given below :

For extrinsic semiconductors; when doping level is increased;

Match List I with List II.

Choose the correct answer from the options given below:

A transistor is connected in common emitter circuit configuration, the collector supply voltage is 10 V and the voltage drop across a resistor of 1000 $\Omega$ in the collector circuit is 0.6 V. If the current gain factor ($\beta$) is 24, then the base current is _________ $\mu$A. (Round off to the Nearest Integer)

A 5V battery is connected across the points X and Y. Assume D1 and D2 to be normal silicon diodes. Find the current supplied by the battery if the +ve terminal of the battery is connected to point X and -ve to point Y.

If an emitter current is changed by 4 mA, the collector current changes by 3.5 mA. The value of β will be :

In connection with the circuit drawn below (assuming a Zener diode circuit with $V_z=10V$, $R_s=500\Omega$, $R_L=2k\Omega$, $V_{in}=15V$), the value of current flowing through 2 kΩ resistor is _________ × 10⁻⁴ A.

The correct relation between $\alpha$ (ratio of $I_C$ to $I_E$) and $\beta$ (ratio of $I_C$ to $I_B$) of a transistor is: