NEET UG 2018 — Electromagnetism

A battery consists of a variable number 'n' of identical cells (having internal resistance 'r' each) which are connected in series. The terminals of the battery are short-circuited and the current $I$ is measured. Which of the graphs shows the correct relationship between $I$ and n?

A metallic rod of mass per unit length $0.5 \mathrm{kg} {m}^{-1}$ is lying horizontally on a smooth inclined plane which makes an angle ${30}^{o}$ with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction $0.25T$ is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is

A set of $n$ equal resistances, of value $R$ each, are connected in series to a battery of emf $E$ and internal resistances $R$. The current drawn is $I$. Now, the $n$ resistance are connected in parallel to the same battery. Then the current drawn from battery becomes $10I$. The value of $n$ is

A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence, the rod gains gravitational potential energy. The work required to do this comes from

An electron falls from rest through a vertical distance $h$ in a uniform and vertically upward directed electric field $E$. The direction of electric filed is now reversed, keeping its magnitude the same. A proton is allowed to fall from rest in it through the same vertical distance $h$. The time of fall of the electron, in comparison to the time of fall of the proton is

An EM wave is propagating in a medium with a velocity $\vec{V}=V\hat{i}$. 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

An inductor $20 mH,$ capacitor $100 \mu F$ and a resistor $50 \Omega$ are connected in series across a source of emf, $V= 10\mathrm{sin}⁡(314t⁡)$. The power loss in the circuit is

Current sensitivity of a moving coil galvanometer is $5 div/mA$ and its voltage sensitivity (angular deflection per unit voltage applied) is $20 div/V$. The resistance of the galvanometer is

The electrostatic force between the metal plates of an isolated parallel plate capacitor $C$ having a charge $Q$ and area $A$, is

The magnetic potential energy stored in a certain inductor is $25\mathrm{mJ}$, when the current in the inductor is $60\mathrm{mA}$ . This inductor is of inductance