Q33 / 143 · NTA Abhyas (JEE Main) 2020 · Physics · Current Electricity

The internal resistance of the cell shown in the figure is negligible. On closing the key k, the ammeter reading changes from 0.25 A to 512 A, then what is the value of resistance R1 (in ohm)?

Figure

Correct answer: 15

Solution

When k was open

Reading of A =E10 A = 0.25,

When k was closed

Reading of A =E10+R110R1=512

⇒ 12 5 + 0.5R1 =10R1

R1 = 15 Ω

Hence, the correct answer is 15.

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