Current Electricity

Assertion : A $60 \mathrm{~W}-220 \mathrm{~V}$ bulb glows more than a $100 \mathrm{~W}-220 \mathrm{~V}$ bulb when they are connected in series across a potential difference. Reason : When they are connected in series,…

Assertion : If the length of the conductor is doubled, the drift velocity will become half of the original value (keeping potential difference unchanged). Reason : At constant potential difference, drift velocity is…

Assertion : A current flows in a conductor only when there is an electric field within the conductor. Reason : The drift velocity of electron in presence of electric field decreases.

In a potentiometer experiment of a cell of emf $1.25 \mathrm{~V}$ gives balancing length of $30 \mathrm{~cm}$. If the cell is replaced by another cell, balancing length is found to be $40 \mathrm{~cm}$. What is the emf…

In the circuit shown, the current through the $5 \Omega$ resistor is

A galvanometer of resistance $100 \Omega$ is converted to a voltmeter of range $10 \mathrm{~V}$ by connecting a resistance of $10 \mathrm{k} \Omega$. The resistance required to convert the same galvanometer to an…

Assertion : An electrical bulb starts glowing instantly as it is switched on. Reason : Drift speed of electrons in a metallic wire is very large.

On increasing the temperature of a conductor, its resistance increases because the

A steady current flows in a metallic conductor of non-uniform cross-section. Which of these quantities is constant along the conductor?

Ten identical cells each of potential $E$ and internal resistance $r$ are connected in series to form a closed circuit. An ideal voltmeter connected across three cells, will read

When a current is passed in a conductor, $5^{\circ} \mathrm{C}$ rise in temperature is observed. If the strength of current is made thrice, rise in temperature will be

Assertion: Current is passed through a metallic wire so that it becomes red hot. When cold water is poured on half of its portion, the rest of the half portion becomes more hot. Reason: Resistance decreases due to…