NTA Abhyas JEE Main2020PhysicsCurrent ElectricityPractice
A milliammeter of range 0-30 mA has internal resistance of 20 Ω . The resistance to be connected in series to convert it into a voltmeter of maximum reading 3 V is
Options
- A49 Ω
- B80 Ω
- C40 Ω
- D30 Ω
Correct answer
B. 80 Ω
Step-by-step solution
R = V I g - G = 3 30 × 10 - 3 - 20 = 10 2 - 20 = 80 Ω