List of top Physics Questions on Electricity

Three infinite plane sheets which have uniform positive surface charge densities $\sigma$, $\sigma$ and $2\sigma$, are arranged parallel to each other with a separation of $d$ as shown in the figure. A spherical Gaussian surface $S$ of radius $d/2$ has its center on the middle sheet. Which of the following statements regarding the electric flux $\Phi_L$ through the left hemisphere and the electric flux $\Phi_R$ through the right hemisphere of the Gaussian surface is correct?

एकसमान रूप से वितरित धनात्मक पृष्ठीय आवेश घनत्व \(\sigma\), \(\sigma\) और \(2\sigma\) वाली तीन सीमारहित समतल चादरें चित्र में प्रदर्शित व्यवस्था के अनुसार एक दूसरे के समानांतर \(d\) दूरी पर रखी हुई हैं। एक \(d/2\) त्रिज्या वाले गोलीय गाउसीय पृष्ठ \(S\) का केन्द्र मध्य में रखी हुई चादर पर स्थित है। गाउसीय पृष्ठ \(S\) के बायें (Left) अर्धगोले से गुजरने वाले वैद्युत फ्लक्स \(\Phi_L\) और दायें (Right) अर्धगोले से गुजरने वाले वैद्युत फ्लक्स \(\Phi_R\) के बारे में निम्न में से कौन सा कथन सही है?

द्रव्यमान \(m_1\) व विद्युत आवेश \(q\) का एक कण, एकसमान बाह्य विद्युत क्षेत्र \(\mathbf{E}\) में, विरामावस्था से प्रारंभ कर \(d\) दूरी \(t_1\) समय में तय करता है। यदि कण का द्रव्यमान \(m_2\) हो तो वही दूरी तय करने में \(t_2\) समय लगता है। \(\frac{t_1}{t_2}\) का अनुपात क्या होगा?

A particle of mass $m_1$ and electric charge $q$ starts from rest under the influence of a uniform external electric field $\mathbf{E}$ to travel a distance $d$ in time $t_1$. If the particle had mass $m_2$, it would take time $t_2$ to travel the same distance. What is the ratio $\frac{t_1}{t_2}$?

A simple pendulum of length $L$, mass $m$ and electric charge $q$ on its bob is oscillating with a time period $T$ under uniform gravity which is in the $-\hat{z}$ direction. Upon applying a uniform electric field $|E|\hat{n}$ (where $\hat{n}$ is a unit vector in the plane of oscillation), the time period of the pendulum decreases. Which of the following statements is NOT correct?

In parallel connection, voltage across each resistor is .

As shown in the figure, the resistance of a galvanometer $G$ can be found by the half-deflection method. Here the resistance $R_2$ is adjusted such that when the key $K$ is closed the deflection in the galvanometer becomes half of the value as compared to when $K$ is open. Half-deflection is obtained at $R_2 = 4\ \Omega$ and thus the galvanometer resistance is found to be $6\ \Omega$. In this half-deflection condition the current (in mA) through the resistor $R_1$ is:

A metal wire of cross-sectional area \(0.5\,\text{mm}^2\) and length \(100\,\text{m}\) is connected across a battery of e.m.f. \(2\,\text{V}\) and internal resistance \(1\,\Omega\). The density, atomic mass and electrical conductivity of the metal are \(6.35 \times 10^3\,\text{kg m}^{-3}\), \(63.5\,\text{gm/mole}\) and \(2 \times 10^8\,\text{mho m}^{-1}\), respectively. Assuming one conduction electron per atom of the metal, the drift velocity (in \(\text{mm s}^{-1}\)) of the electrons in the wire is:
(Take Avogadro’s number as \(6 \times 10^{23}\) and charge of the electron as \(1.6 \times 10^{-19}\,\text{C}\).)

A potentiometer wire is 10m long and has a resistance of $18\,\Omega$. It is connected to a battery of emf 5V and internal resistance $2\,\Omega$. Calculate the potential gradient along the wire.

A wire of resistance $R$ is stretched to double its original length. Its new resistance will be

A wire is stretched to double its length. New resistance becomes:

If across a resistance, voltage applied is \((20 \pm 0.2)\,\text{V}\) and the current passing through it is \((10 \pm 0.1)\,\text{A}\). Find the maximum error in resistance.

Complete the following: A substance whose resistance becomes almost negligible at a temperature near absolute zero is called a __________.

Consider two waves, which are given by $y_1(x, t) = A \sin(kx - \omega t)$ and $y_2(x, t) = \sqrt{3}A \cos(kx - \omega t)$, where $k$ is the wave number and $\omega$ is the angular frequency. The amplitude of the resultant waveform obtained by the superposition of the two waves is $A_s$ and its phase difference with $y_1$ is $\phi_s$. What are $A_s$ and $\phi_s$?

If 5A current flows through an electric iron, it produces 50J heat in one second, the potential across the electric iron will be

The resistor of resistance \(R\) is connected between the terminals of a cell of emf \(E\) and internal resistance \(r\). The current \(I\) through the circuit is

Consider two point charges \(+q\) and \(+2q\) fixed on the \(x-y\) plane at \((-\ell/2, 0)\) and \((+\ell/2, 0)\) respectively. Another point charge \(-q\) having mass \(m\) is released from rest at \((0, \frac{\sqrt{3}}{2}\ell)\) on the \(x-y\) plane, as shown in the figure. The permittivity of free space is \(\epsilon_0\). What is the acceleration of the charge \(-q\) at the time of release?