Question

Calculate the heat dissipated across $6\Omega$ and $4\Omega$ resistors in 30 seconds.

• A. $30\text{J},45\text{J}$
• B. $45\text{J},30\text{J}$
• C. $125\text{J},187.5\text{J}$
• D. $187.5\text{J},125\text{J}$

Answer 1

The correct option is B $45\text{J},30\text{J}$

Heat dissipated across a resistor$=I^{2}Rt$
Since the resistors are in series, current will be the same across them.
$I=\frac{V}{R}=\frac{5}{10}=0.5A$.
H across $R_1=\left(0.5\right)\times \left(0.5\right)\times 6\times 30=45J$.
H across $R_2=\left(0.5\right)\times \left(0.5\right)\times 4\times 30=30J$.