Two electric bulbs A and B are marked 40 W – 220 V and 60 W – 220 V respectively. Which one of the two has a greater resistance?

Should the resistance of an ammeter be low or high? Give reason.

In an experiment to study the relationship between the potential difference across a resistor and the current through it, a student recorded the following observations:

Find in which one of the above sets of readings the trend is different from others and must be rejected. Calculate the mean value of resistance of the resistor based on the remaining sets of readings.

a. Table gives the resistivity of three materials in (in Ω m) A, B, C.

Which one of them is the best conductor? And which is an insulator and why?

b. A wire of resistivity P is stretched to twice its length. What will be its new resistivity?

How can three resistance of 2, 3 and 6 ohms be connected so as to give a total resistance of 1 ohm?