Electricity and Magnetism MCQ question and answer with solution | Physics Gk MCQs

Definition: In electronic circuits, certain components are used to control the flow of direct current (DC) and alternating current (AC). A capacitor plays a crucial role in blocking DC while allowing AC to pass.

Step 1: Understanding the behavior of circuit elements:

Resistance: It opposes both DC and AC but does not block DC completely.

Capacitance: A capacitor blocks DC because, at steady-state, the dielectric between its plates prevents continuous DC flow. However, it allows AC to pass by charging and discharging cyclically.

Inductance: An inductor primarily opposes changes in current but does not block DC.

Diode: It allows current to flow in one direction and blocks reverse current, but it does not specifically block DC.

Step 2: Since a capacitor effectively blocks DC while allowing AC to pass, the correct answer is Capacitance (Option B).

Explanation:
The work done to move a charge between two points is related to the potential difference between those points.
We can use the formula: Work Done (W) = Charge (Q) x Potential Difference (V)
In this case, the charge (Q) is 5 Coulombs (C) and the potential difference (V) is 15 Volts (V).
So, W = 5 C x 15 V = 75 Joules (J)
Therefore, the correct answer is Option C: 75 J.

To calculate the energy consumed by the electric iron in one day, we can use the formula:
Energy = Power × Time
Given: Power of the electric iron P = 750W Time the electric iron is used per day t = 8hours
First, we need to convert the time from hours to hours: t=8×1=8 hours
Now, we can calculate the energy consumed: Energy=750×8=6000 watt-hours
Since 1 kilowatt-hour (kWh) is equal to 1 unit of electricity, we need to convert the energy from watt-hours to units: Energy in units = $$\frac{6000}{1000}$$ = 6 units
Therefore, the energy consumed in one day by the electric iron is 6 units.