Question

An electrically heated coil is immersed in a calorimeter containing 360 gm of water at 10⁰C. The coil consumes energy at the rate of 90W. The water equivalent of calorimeter & coil is 40 gm. The temperature of water after 10 minutes is-

• A. 4.214⁰C
• B. 42.14ŗC
• C. 30⁰C
• D. None of these

Answer 1

Answer: (B)

42.14ŗC

Answer 2

P = $\frac{E}{t}$ = $\frac{\Delta Q}{t}$ = $\frac{ms\Delta\theta}{t}$

Ž Dq = $\frac{Pt}{ms}$ = $\frac{90 \times 10 \times 60}{400 \times 10^{- 3} \times 4200}$

Ž q₂ – q₁ = 32.14⁰C

q₂ = 32.14⁰C + q₁ = 42.14⁰C