WAEC Physics 2020 Objective — Question 19
Question 19 of 50 from the West African Examinations Council (WAEC) Physics 2020 Objective paper, with the correct answer and a full explanation.
Advertisement
A moving-coil galvanometer which gives a full-scale deflection with 0.005 A is converted to a voltmeter, reading up to 5 V using an external resistance of 975 ohm. What is the resistance of the metre?
- A. 0.25 ohm
- B. 2.50 ohm
- C. 25.00 ohmCorrect
- D. 250.00 ohm
Explanation
This involves converting an ammeter to a voltmeter using a multiplier (a high resistance resistor in series with the galvanometer). Resistance of the multiplier Rm = V/I - Rg = 5/0.005 - 975 = 1000-975 = 25 ohm.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.