$A$ wire is $1.0 \, m$ long,$0.2 \, mm$ in diameter and has a resistance of $10 \, \Omega$. Calculate the resistivity of its material.

$A$ house is fitted with $5$ tubes each of $40 \, W$. If all the tubes are lighted for $20$ hours and if the cost of electrical unit is ₹ $0.50$,the total cost of electricity consumed is (in ₹)

$(a)$ Name the effect of electric current which is utilised in the working of an electrical fuse.
$(b)$ How is a fuse connected in a domestic circuit?

The electric current flowing through any conductor is directly proportional to the electric potential difference across the conductor. Which law is this?

The following table provides the resistivity of three samples:

Sample	$A$	$B$	$C$
Resistivity	$1.6 \times 10^{-8} \Omega \cdot m$	$5.2 \times 10^{-8} \Omega \cdot m$	$100 \times 10^{-6} \Omega \cdot m$

Which of them is suitable for heating elements of electrical appliances and why?

$(a)$ Define the term 'volt'.
$(b)$ State the relation between work,charge,and potential difference for an electric circuit. Calculate the potential difference between the two terminals of a battery,if $100 \ J$ of work is required to transfer $20 \ C$ of charge from one terminal of the battery to the other.