$(a)$ Name the instrument/device used to measure electric current in a circuit.
$(b)$ How is an ammeter connected in a circuit to measure current flowing through it?

In a household electric circuit,different appliances are connected in parallel to one another. Give two reasons for this. An electrician puts a fuse of rating $5 \, A$ in that part of a domestic electrical circuit in which an electrical heater of rating $1.5 \, kW, 220 \, V$ is operating. What is likely to happen in this case and why? What change,if any,needs to be made?

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

Study the $V - I$ graph for a resistor as shown in the figure and prepare a table showing the values of $I$ (in amperes) corresponding to four different values of $V$ (in volts). Find the value of current $I$ (amperes) for $V=10$ volts. How can we determine the resistance of the resistor from this graph?

The rating of an electric heater is $1100 \ W, 220 \ V$. Calculate its resistance when it operates at $220 \ V$. Also,calculate the energy consumed in $kWh$ in the month of November,if the heater is used daily for four hours at the rated voltage.

Given below is a circuit showing current flowing in it. Identify each component $A, B, C, D$ of this circuit.