Question

The energy supplied by a power plant is $40\times {10}^6\text{kWh}$. It is supplied by annihilation of matter, the mass that is annihilated is-
[Use $1\text{kWh}=36\times {10}^5\text{J}$]

• A. $16\text{g}$
• B. $1.6\text{a.m.u}$
• C. $1.6\text{g}$
• D. $1.6\text{kg}$

Answer 1

The correct option is C $1.6\text{g}$

Given,

$E=40\times {10}^6\text{kWh}=4\times {10}^7\times 36\times {10}^5\text{J}[\because 1\text{kWh}=36\times {10}^5\text{J}]$

Using, mass-energy equivalence, $E=m{c}^2$

$4\times 36\times {10}^{12}=m\times (3\times {10}^8{)}^2$

$4\times 36\times {10}^{12}=m\times 9\times {10}^{16}$

$m=16\times {10}^{-4}\text{kg}\text{(or)}1.6\text{g}$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(C\right)$ is the correct answer.