Question

A constant current of 3A flows through a conductor having potential difference of 200V. Find heat developed in conductor in 25s.

Hint:

The formula $H = V I t$ is generally the fastest method to compute dissipated heat when both voltage and current are explicitly provided.
It is mathematically identical to the alternative forms $H = I^2 R t$ and $H = \frac{V^2}{R} t$.

Answer 1

Step 1: Understanding the Concept:
When an electric current flows steadily through a conductor across a specific potential difference, electrical work is done.
This work is entirely dissipated into the surrounding environment as thermal energy, a phenomenon widely known as Joule's heating effect.
Step 2: Key Formula or Approach:
The total heat $H$ developed in a conductor over a time period is given by the foundational formula $H = V I t$.
Here, $V$ stands for the potential difference, $I$ is the constant current, and $t$ is the elapsed time.
Step 3: Detailed Explanation:
The given values extracted from the problem statement are:
Constant Current $I = 3\text{ A}$.
Potential difference $V = 200\text{ V}$.
Time duration $t = 25\text{ s}$.
Substitute these explicit values directly into the heating formula:
\[ H = 200 \times 3 \times 25 \] \[ H = 600 \times 25 \] \[ H = 15000\text{ J} \] To express this large standard value in a more concise form like kilojoules (kJ), simply divide by 1000:
\[ H = 15\text{ kJ} \] Step 4: Final Answer:
The total heat developed in the conductor is $15\text{ kJ}$.