CBSE Class 12 · 2006 · All India · Magnetic Effects of CurrentShort Answer

Which of the two, an ammeter or a milliammeter, has a higher resistance and why?

Answer: The milliammeter has the higher resistance.

Solution

Both are galvanometers with a shunt

S = \frac{I _{g}}{I - I _{g}} G

. A milliammeter measures a smaller maximum current

I

, so it needs a larger shunt than an ammeter. A larger shunt in parallel makes the overall (parallel) resistance larger, so the milliammeter has the higher resistance.

CBSE Class 12 Board · 2006 · All India · Subjective

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