Question 19
Current ElectricityWhich of the following statements is incorrect? The sensitivity of a galvanometer which incorporates an optical lever arrangement may be increased by providing:
- A.a larger number of turns in the coil
- B.a thinner suspension with a small torsional control
- C.a special alloy permanent magnet which gives a high magnetic flux
- D.all of the above
- E.a light source with a greater intensity.
Show the answer and explanation
Answer: E (a light source with a greater intensity.)
Explanation
More turns, a weaker (thinner) suspension and a stronger magnet all give a bigger deflection per unit current, so A to C are correct. A brighter lamp only makes the spot easier to see; it does not change the deflection, so E is the incorrect statement.