A household study group records the name-plates of three devices in their study room…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Electric Circuits · Electric Circuits
Problem
A household study group records the name-plates of three devices in their study room as follows:
• Desk lamp: 40 W, 200 V
• Laptop charger: 60 W, 200 V
• Table-fan: 45 W, 200 V
Answer the questions that follow without performing elaborate numerical calculations.
(i) Define the term "rated power" of an electrical appliance.
(ii) Distinguish clearly between electrical power and electrical energy on the basis of definition, unit and physical meaning. State any two points of difference.
(iii) For the given mains supply of 200 V, arrange the three devices in the increasing order of current drawn. Give suitable reasoning based on their name-plate information.
(iv) If each device is used exactly 5 h every day, identify which one will contribute the largest amount to the monthly electricity bill. Justify qualitatively, showing the logical steps in your comparison (exact arithmetic is not required).