Physics Test - ...

A convex lens of focal length 50 cm and a concave lens of focal length 25 cm are placed in contact with each other. Then the equivalent focal length of the combination will be:

A rectangular coil of length \(40\) cm and width \(10\) cm consists of \(10\) turns and carries a current of \(16\) A. The coil is suspended such that the normal to the plane of the coil makes an angle of \(60^{\circ}\) with the direction of a uniform magnetic field of magnitude \(0.60\) T. Find the magnitude of the torque experienced by the coil.

Consider the geometry shown in the figure of a silicon step junction:

The uniform impurity doping concentrations of \(\mathrm{N}_{\mathrm{a}}=5 \times 10^{15} \mathrm{~cm}^{-3}\), \(\mathrm{n}_{\mathrm{i}}=1.5 \times 10^{10} \mathrm{~cm}^{-3}\).

If the applied voltage \(V_{a}=\frac{1}{2} V_{b i}\) then, the value of \(V_{a}\) will be:

Match Column - I and Column - II and choose thecorrect match from the given choices.

The relation between radius of curved road and banking angle is:

Find the electric charge \({Q}_{1}\) on plates of capacitor \({C}_{1}\), shown in Figure 3 below:

A transformer is used to light a 100 W and 110 V lamp from a 220 V mains. If the current is 0.5 amp, the efficiency of the transformer is approximate:

A wire of resistance 'R' is cut into 'n' equal parts. These parts are then connected into parallel. The equivalent resistance value will be ______.

The earth's magnetic induction at a certain point is \(7 \pi \times 10^{-5}\) Wb/m\(^{2}\). This is to be annulled by the magnetic induction at the center of a circular conducting loop of radius \(5 cm\). The required current in the loop is: \((\mu_{0}=4 \pi \times 10^{-7}\) TA\(^{-1}\) m\()\)

The objective lens of a refracting telescope is a: