A family uses 8 kW of power. (a) Direct | Class 11 Physics Chapter Work Energy and Power, Work Energy and Power NCERT Solutions

Welcome to the NCERT Solutions for Class 11 Physics - Chapter Work Energy and Power. This page offers a step-by-step solution to the specific question from Exercise 1, Question 23: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 23:

A family uses 8 kW of power. (a) Direct solar energy is incident on the horizontal surface at an average rate of 200 W per square meter. If 20% of this energy can be converted to useful electrical energy, how large an area is needed to supply 8 kW? (b) Compare this area to that of the roof of a typical house.

Answer:

(a) 200 m2

(a) Power used by the family, P = 8 kW = 8 × 103 W

Solar energy received per square metre = 200 W

Efficiency of conversion from solar to electricity energy = 20 %

Area required to generate the desired electricity = A

As per the information given in the question, we have:

8 x 103 = 20% x (A × 200)

= 20/100 x A x 200

∴ A = 8 x 103 / 40 = 200 m2

(b) The area of a solar plate required to generate 8 kW of electricity is almost equivalent to the area of the roof of a building having dimensions 14 m × 14 m.


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Welcome to the NCERT Solutions for Class 11 Physics - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 23: A family uses 8 kW of power. (a) Direct solar energy is incident on the horizontal surface at an ave....