Explain the factors affecting the sensitivity of a moving-coil galvanometer and the effect of adding bulbs in series.

Here are the solutions to question 11:

a) Two factors that determine the sensitivity of a moving-coil galvanometer are:

• The strength of the magnetic field in which the coil rotates.
• The number of turns in the coil.

b)

(i) When more bulbs are added in series with the first one:

• The total resistance of the circuit increases.
• The brightness of each bulb decreases.

(ii)
(α) The circuit diagram for reducing the current passing through a galvanometer by means of a resistor in series is shown below:

      +---[ Resistor (R) ]---+
      |                      |
      ---[ Galvanometer (