An electrical device operate at 12 A current and 120 V D.C. If it is connected with 250 V and 30 Hz AC. then power consumption :-

Options

A. 625 N
B. 1250 N
C. 6250 W
D. zero

Answer

To solve the problem step by step, we will follow the reasoning provided in the video transcript.

### Step 1: Determine the resistance of the device
The electrical device operates at a direct current (DC) of 12 A and a voltage of 120 V. We can calculate the resistance (R) using Ohm's law, which states:

\[ R = \frac{V}{I} \]

Where:
- \( V = 120 \, \text{V} \)
- \( I = 12 \, \text{A} \)

Substituting the values:

\[ R = \frac{120 \, \text{V}}{12 \, \text{A}} = 10 \, \Omega \]

### Step 2: Calculate the power consumption in AC
Now that we have the resistance, we need to calculate the power consumption when the device is connected to an AC source. The given AC voltage is 250 V (RMS), and we will use the formula for power in AC circuits:

\[ P = \frac{V_{\text{rms}}^2}{R} \]

Where:
- \( V_{\text{rms}} = 250 \, \text{V} \)
- \( R = 10 \, \Omega \)

Substituting the values:

\[ P = \frac{(250 \, \text{V})^2}{10 \, \Omega} \]

Calculating \( (250)^2 \):

\[ (250)^2 = 62500 \]

Now substituting back into the power formula:

\[ P = \frac{62500}{10} = 6250 \, \text{W} \]

### Final Answer
The power consumption of the device when connected to 250 V AC is:

\[ P = 6250 \, \text{W} \]

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