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Question

Physics Question on Current electricity

Given below are two statements:

Statement I : A uniform wire of resistance 80 Ω is cut into four equal parts. These parts are now connected in parallel. The equivalent resistance of the combination will be 5 Ω.

Statement II : Two resistances 2R and 3R are connected in parallel in a electric circuit. The value of thermal energy developed in 3R and 2R will be in the ratio 3 : 2.

In the light of the above statements, choose the most appropriate answer from the option given below.

A

Both statement I and statement II are correct

B

Both statement I and statement II are incorrect

C

Statement I is correct but statement II is incorrect

D

Statement I is incorrect but statement II is correct

Answer

Statement I is correct but statement II is incorrect

Explanation

Solution

Statement 1 -

R = 80 Ω

R1=R2=R3=R4=20 Ω In parallel Req=204=5ΩR_{eq}=\frac{20}{4}=5 Ω

**Statement 2 - **

Pth=v2RP1P2=(R2R1)=23P_{tℎ}=\frac{v^2}{R}\frac{P1}{P2}=(\frac{R2}{R1})=\frac{2}{3} (where P is Power)

So, Statement I is correct but statement II is incorrect.