List of top Physics Questions

A piece of wire of resistance 4 ohm is bent through 180 at its mid point and the two halves are twisted together. Then the resistance is
A potentiometer wire of length $100 \,cm$ has a resistance of $10 \,\Omega$. It is connected in series with a resistance and a cell of emf $2 \,V$ and of negligible internal resistance. A source of emf $10 \,mV$ is balanced against a length of $40 \,cm$ of the potentiometer wire. What is the value of external resistance ?
A voltmeter of resistance $R$ is to be used to measure the potential difference across a resistance $r$. The nearest reading in the absence of voltmeter ?
According to the Kirchhoffs law the sum of the products of current and resistance as well as emfs in a closed loop is :
All of the following statements are true except
An electric bulb rated 220V, 100W is connected to a source of 220 (0.8)V then actual power will be
An electric heater is connected to the voltage supply. After few seconds, current gets its steady value then its initial current will be
An electric lamp is marked 100 W, 220 V. If it operates at 200 V, the current through it will be:
Insulators do not allow flow of current through them Insulators have no free charge carriers
Potentiometer is used only to compare potential differences The potentiometer draws current from the voltage source being measured
The resistance of a conductor decreases with increase in cross-sectional area On increasing the cross-sectional area of a conductor, more current will flow through the conductor
Calculate the steadystate current in the $2\,\Omega$ resistor shown in the circuit in the figure.
The internal resistance of the battery is negligible and the capacitance of the condenser $C$ is $0.2\, \mu F$.
For higher sensitivity essential for the potentiometer is
For ohmic conductor the drift velocity $\upsilon_d$ and the electric field $E$ applied across it are related as:
If potential difference across a conductor, having a material of specific resistance $\rho$ remains constant, then according to Joules law, heat developed in the conductor is directly proportional to :
If the radius of a wire carrying current is doubled, the drift velocity of the electrons will be
In a metre bridge experiment null point is obtained at $20\,cm$ from one end of the wire when resistance $X$ is balanced against another resistance $Y$. If $X < Y$, then where will be the new position of the null point from the same end, if one decides to balance a resistance of $4\, X$ against $Y$ ?
In a potentiometer of $10$ wires, the balance point is obtained on the $7^{th}$ wire. To shift the balance point to $9^{th}$ wire, we should
In a wheatstone bridge if the battery and galvanometer are interchanged then the deflection in galvanometer will
In an atom electrons revolves around the nucleus along a path of radius $0.72 \,?$ making $9.4 \times 10^{18}$ revolution per second. The equivalent current is $(e = 1.6 \times 10^{-19}\, C)$
In parallel combination of $n$ cells, we obtain
In the circuit given below the ammeter reading is zero.What is the value of the resistance R?
In the series combination of $n$ cells each cell having emf $\varepsilon$ and internal resistance $r$. If three cells are wrongly connected, then total emf and internal resistance of this combination will be
In the series combination of two or more than two resistances
Match column $I$ with column $II$ and select the correct option from the given codes.