RRB Junior Engineer / DMS / CMA 2019 · Question 3546 of 3719
R = vcos θ × ⇒ g 2vsin θ R = g 2v sinθcosθ 2 2sinθ.cosθ = sin2θ ⇒R = g v sin2θ 2 Explanation: CONCEPT: Solar cooker: It is a device that uses the energy of sunlightto heat or cook food A concave mirror is that mirror whose reflecting surface is toward the center of the curvature . It is also known as a converging mirror . EXPLANATION : A solar cooker contains a box made of insulating material, with its inner surfaces blackened . The top is closed by a glass sheet . Glass sheet present in the solar cooker easily passes the radiation into the solar cooker and the radiation gets absorbed and cannot pass back out through the glass . Thus, the glass sheet produces a greenhouse effect in the solar cooker. Therefore option 3 is correct.
Source: RRB JE 2019 (CBT 2) (ME) Previous Year Paper (31 Aug 2019) — prepp.in solved-paper PDF (answer key with explanations) · reliable-secondary
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