Physics Paper 2, 2019

Physics Paper 2 WASSCE (PC), 2019

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Weakness/Remedies

Candidate's Strength

Question 11

1. State Flemming’s Left Hand Rule.
2. State two factors that will enhance the sensitivity of a moving-coil galvanometer.
1. State two advantages of a moving-coil galvanometer.
2. State two disadvantages of a moving-coil galvanometer
The diagram above illustrates a galvanometer of full-scale-deflection 20mA and internal resistance of 10, converted to an ammeter reading up to 6A. Calculate the value of R.
State two:
1. applications of static electricity;
2. industrial hazards of static electricity.

Observation

The expected answer is:

1. Fleming’s Left Hand Rule
  If the thumb and the first two fingers of the left hand are held mutually at right angles to each other, the first finger pointing the direction of the Field, the second finger in the direction of Current, then the thumb points in the direction of Motion.
2. Factors that enhance the sensitivity of a moving coil galvanometer
  - weaker (phosphor) hair spring
  - larger number of turns in the coil
  - increase area of coil
  - strongest magnet
1. - Very sensitive to small changes in current
  - Can be upgraded to measure higher currents
  - Well damped/robust
  - Has uniform / linear scale
2. Disadvantages of moving coil galvanometer
  - Can only measure direct current
  - Affected by current change
  - Their internal resistance affects the current and being measured

Calculation of the value of R

1. Industrial hazards of static electricity
  - Industrial hazards of static electricity
  - Explosions when fuelling aircraft
  - Damage to integrated circuits
  - Electric shock