Question

In the amount of water of mass 20 g at 0°C is mixed with 40 g of water at 10°C, the final temperature of the mixture is ______.

Options

• 5.5°C

• 0°C

• 20°C

• 6.66°C

Answer 1

In the amount of water of mass 20 g at 0°C is mixed with 40 g of water at 10°C, the final temperature of the mixture is 6.66°C.

Explanation:

If θ is the temperature of the mixture, then

Heat gained by water at 0°C = Heat lost by water at 10°C

⇒ `C_1m_1(theta - 0) = C_2m_2(10 - theta)`

Here, `m_1 = 20 g, m_2 = 40 g` and `C_1 = C_2`

⇒ `m_1theta = m_2(10 - theta) ⇒ 20theta = 40(10 - theta)`

⇒ `theta = 20/3 = 6.66^circC`