A large number of free electrons are present in metals yet no current flows in the absence of electric potential across it. Explain the statement with reason.
A large number of free electrons are present in metals, yet no current flows. It is because the eletrons move only if there is a difference of electric pressure - called as the potential difference along the conductor. The potential difference sets the charges in motion in the conductor and produces an electric current.
If resistors are connected in series, the current through each resistor remains the same.
From the listed electrical devices, which releases heat energy that is not appreciated?
Define current, give its mathematical expression. What is its $SI$ unit ?
The potential difference across the terminals of a cell is $1.5$ volt. If it is connected with a resistance of $30$ $ohms$, calculate the current flowing through the circuit.
The resistivity of all pure metals increases with increase in temperature.