List of practice Questions

Figure shows a straight wire length \(l\) carrying current \(i\). The magnitude of magnetic field produced by the wire at point \(P\) is

Zener diode is used for

Two light sources are said to be coherent if they are obtained from

A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The number of turns is \(n\) and the cross-sectional area of the coil is \(A\). When the coil turns through \(180^\circ\) about its diameter, the charge flowing through the coil is \(Q\). The total resistance of the circuit is \(R\). What is the magnitude of the magnetic induction?

The attenuation of a calf fibre is mainly due to

An arc of radius \(r\) carries charge. The linear density of charge is \(\lambda\) and the arc subtends an angle \(\dfrac{\pi}{3}\) at the centre. What is electric potential at the centre?

In Young's double slit experiment, the spacing between the slits is \(d\) and wavelength of light used is \(6000\,\text{\AA}\). If the angular width of a fringe formed on a distance screen is \(1^\circ\), the value of \(d\) is

An electric dipole consists of two opposite charges of magnitude \(q = 1\times 10^{-6}\,C\) separated by \(2.0\,cm\). The dipole is placed in an external field of \(2\times 10^{5}\,NC^{-1}\). What maximum torque does the field exert on the dipole? How much work must an external agent do to turn the dipole end to end, starting from position of alignment (\(\theta = 0^\circ\))?

The electron of hydrogen atom is considered to be revolving round a proton in circular orbit of radius \(h^2/me^2\) with velocity \(e^2/h\), where \(h = h/2\pi\). The current \(i\) is

Which of the following rays is emitted by a human body?

A proton of mass \(1.67\times 10^{-27}\,kg\) enters a uniform magnetic field of \(1\,T\) at point \(A\) shown in figure with a speed of \(10^{7}\,m\,s^{-1}\). The magnetic field is directed perpendicular to the plane of the paper downwards. If the proton emerges out of the magnetic field at point \(C\), then the distance \(AC\) and the value of angle \(\theta\) will respectively be

A neutral water molecule (\(H_2O\)) in its vapour state has an electric dipole moment of magnitude \(6.4\times 10^{-30}\,C\,m\). How far apart are the molecules centres of positive and negative charges?

A straight wire carrying current \( i \) is turned into a circular loop. If the magnitude of magnetic moment associated with it in MKS unit is \( M \), the length of wire will be

The ratio of the amounts of heat developed in the four arms of a balance Wheatstone bridge, when the arms have resistances \(P = 100\,\Omega\), \(Q = 10\,\Omega\), \(R = 300\,\Omega\) and \(S = 30\,\Omega\) respectively is

An electric kettle takes \(4\,A\) at \(220\,V\). How much time will it take to boil \(1\,kg\) of water from temperature \(20^\circ C\)? The temperature of boiling water is \(100^\circ C\).

Magnetic field at the centre of a circular loop of area is \(B\). The magnetic moment of the loop will be

Three separate samples of a solution of a single salt gave these results. One formed a white precipitate with excess ammonia solution, one formed a white precipitate with dil. $HCl$ solution and one formed a black precipitate with $H_{2} S$. The salt could be

Liebig? method is used for the estimation of

From the top of a cliff 25 m high the angle of elevation of a tower is found to be equal to the angle of depression of the foot of the tower. The height of the tower is

Minamata disease is due to pollution of

The value of $\cos^{-1}x + \cos^{-1} \left(\frac{x}{2} + \frac{1}{2} \sqrt{3-3x^{2}}\right) ; \frac{1}{2} \le x \le 1 $ is

The slope of the tangent to the hyperbola $2x^2 - 3y^2 = 6$ at $(3, 2)$ is

The solution of differential equation $2x \frac{dy}{dx} - y = 3$ represents a family of

If $I_{m}=\int\limits_{1}^{e}(\ln x)^{m} d x$, where $m \in N$, then $I_{10}+10 I_{9}$ is equal to -