List in a tabular form two differences between a voltmeter and an ammeter.

Why are alloys used to make standard resistors?

$(a)$ Define potential difference between two points in a conductor.
$(b)$ Name the instrument used to measure the potential difference in a circuit. How is it connected?
$(c)$ $A$ current of $2 \, A$ passes through a circuit for $1$ minute. If the potential difference between the terminals of the circuit is $3 \, V$, what is the work done in transferring the charges?

Who discovered the electron?

Three resistors of $5 \, \Omega$,$10 \, \Omega$,and $15 \, \Omega$ are connected in series,and the combination is connected to a battery of $30 \, V$. An ammeter and a voltmeter are connected in the circuit. Draw a circuit diagram to connect all the devices in the correct order. What is the current flowing through the circuit and the potential difference across the $10 \, \Omega$ resistor?

$A$ hot plate of an electric oven connected to a $220 \ V$ line has two resistors $A$ and $B$ each of $22 \ \Omega$ resistance. These resistors may be used separately,in series,or in parallel. Find the current flowing in all the three cases.