Power of a lamp is $60\, W$. Find the energy in joules consumed by it in $1\, s$. (in $, J$)

When three resistors of $5 \Omega$,$10 \Omega$,and $30 \Omega$ are connected in parallel in a circuit,what will be the equivalent resistance?

An electric appliance draws a current of $0.4\, A$ when the voltage is $200\, V$. Calculate the amount of charge flowing through it in one hour.

$(a)$ Resistivity of iron is $10 \times 10^{-8} \; \Omega m$ and of mercury is $94 \times 10^{-8} \; \Omega m$. Which among iron and mercury is a better conductor? Give reason.
$(b)$ Resistivity of a material $A$ is in the range of $10^{10}-10^{14} \; \Omega m$ while that of $B$ is in the range of $10^{-6}-10^{-8} \; \Omega m$. Which of the two will behave as an insulator and why?

State Ohm's law. How can it be verified experimentally? Does it hold good under all conditions? Comment.

State Ohm's law.