Electromagnetism PYQ — Page 36

A proton, a deuteron and an $\alpha$-particle with same kinetic energy enter into a uniform magnetic field at right angle to magnetic field. The ratio of the radii of their respective circular paths is :

Match List - I with List - II <table class="pyq-table"><tbody><tr><td></td><td>List-I</td><td></td><td>List-II</td></tr><tr><td>(a)</td><td>UV rays</td><td>(i)</td><td>Diagnostic tool in medicine</td></tr><tr><td>(b)</td><td>$X$-rays</td><td>(ii)</td><td>Water purification</td></tr><tr><td>(c)</td><td>Microwave</td><td>(iii)</td><td>Communication, Radar</td></tr><tr><td>(d)</td><td>Infrared wave</td><td>(iv)</td><td>Improving visibility in foggy days</td></tr></tbody></table>Choose the correct answer from the options given below :

As show in the figure, in steady state, the charge stored in the capacitor is _____$\times {10}^{-6}C$. 

A metal surface is illuminated by a radiation of wavelength $4500\overset{\circ }{A}$. The ejected photo-electron enters a constant magnetic field of $2\mathrm{mT}$ making an angle of $90^{\circ}$ with the magnetic field. If it starts revolving in a circular path of radius $2\mathrm{mm}$, the work function of the metal is approximately

The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has

The current flowing through an ac circuit is given by $I=5\mathrm{sin}(120\pi t)A$. How long will the current take to reach the peak value starting from zero?

As shown in the figure, a metallic rod of linear density $0.45\mathrm{kg}{m}^{-1}$ is lying horizontally on a smooth incline plane which makes an angle of $45^{\circ}$ with the horizontal. The minimum current flowing in the rod required to keep it stationary, when $0.15T$ magnetic field is acting on it in the vertical upward direction, will be (Use $g=10m{s}^{-2}$) 

A force of $10N$ acts on a charged particle placed between two plates of a charged capacitor. If one plate of capacitor is removed, then the force acting on that particle will be.

A certain charge $Q$ is divided into two parts $q$ and $(Q-q).$ How should the charges $Q$ and $q$ be divided so that $q$ and $(Q-q)$ placed at a certain distance apart experience maximum electrostatic repulsion?

Four identical rectangular plates with length, $l=2\mathrm{cm}$ and breadth, $b=\frac{3}{2}\mathrm{cm}$ are arranged as shown in figure. The equivalent capacitance between $A$ and $C$ is $\frac{x{\epsilon }_{0}}{d}.$ The value of $x$ is _______. (Round off to the Nearest Integer) 

For full scale deflection of total $50$ divisions, $50\mathrm{mV}$ voltage is required in galvanometer. The resistance of galvanometer if its current sensitivity is $2\mathrm{div}/\mathrm{mA}$ will be:

In a parallel plate capacitor set up, the plate area of capacitor is $2{m}^{2}$ and the plates are separated by $1m$. If the space between the plates are filled with a dielectric material of thickness $0.5m$ and are $2{m}^{2}$ (see figure) the capacitance of the set-up will be ${\epsilon }_{0}$ ________. (Dielectric constant of the material $=3.2$) (Round off to the Nearest Integer) 

In a ferromagnetic material, below the curie temperature, a domain is defined as:

An X-ray tube is operated at $1.24$ million volt. The shortest wavelength of the produced photon will be:

An electric bulb of $500W$ at $100V$ is used in a circuit having a $200V$ supply. Calculate the resistance $R$ to be connected in series with the bulb so that the power delivered by the bulb is $500W$.

Find out the surface charge density at the intersection of point $x=3m$ plane and $x$-axis, in the region of uniform line charge of $8\mathrm{nC}{m}^{-1}$ lying along the $z$-axis in free space.

Consider a galvanometer shunted with $5\Omega$ resistance and $2%$ of current passes through it. What is the resistance of the given galvanometer?

A steel rod with $y=2.0\times {10}^{11}N{m}^{-2}$ and $\alpha ={10}^{-5}{C\circ }^{-1}$ of length $4m$ and area of cross-section $10{\mathrm{cm}}^{2}$ is heated from $0^{\circ}C$ to $400^{\circ}C$ without being allowed to extend. The tension produced in the rod is $x\times {10}^{5}N$ where the value of $x$ is $_________.$

Consider a $72\mathrm{cm}$ long wire $AB$ as shown in the figure. The galvanometer jockey is placed at $P$ on $AB$ at a distance $x\mathrm{cm}$ from $A$. The galvanometer shows zero deflection.  The value of $x$, to the nearest integer, is

Match List - I with List - II.<table class="pyq-table"><tbody><tr><td colspan="2" rowspan="1">List-I</td><td colspan="2" rowspan="1">List-II</td></tr><tr><td>(a)</td><td>Source of microwave frequency</td><td>(i)</td><td>Radioactive decay of nucleus</td></tr><tr><td>(b)</td><td>Source of infrared frequency</td><td>(ii)</td><td>Magnetron</td></tr><tr><td>(c)</td><td>Source of Gamma Rays</td><td>(iii)</td><td>Inner shell electrons</td></tr><tr><td>(d)</td><td>Source of $X$-rays</td><td>(iv)</td><td>Vibration of atoms and molecules</td></tr><tr><td></td><td></td><td>(v)</td><td>LASER</td></tr><tr><td></td><td></td><td>(vi)</td><td>RC circuit</td></tr></tbody></table>Choose the correct answer from the options given below:

A series LCR circuit driven by $300V$ at a frequency of $50\mathrm{Hz}$ contains a resistance $R=3k\Omega$, an inductor of inductive reactance ${X}_{L}=250\pi \Omega$ and an unknown capacitor. The value of capacitance to maximise the average power should be: $(\text{take}{\pi }^{2}=10)$

A resistor develops $500J$ of thermal energy in $20s$ when a current of $1.5A$ is passed through it. If the current is increased from $1.5A$ to $3A$, what will be the energy developed in $20s$.

$512$ identical drops of mercury are charged to a potential of $2V$ each. The drops are joined to form a single drop. The potential of this drop is $V$ in Volt.

The angular frequency of alternating current in a L-C-R circuit is $100\mathrm{rad}{s}^{-1}$. The components connected are shown in the figure. Find the value of inductance of the coil and capacity of condenser.