Questions for 1-10-2007

1. In a dark room with ambient temperature T0, a black body is kept at a temperature T. Keeping the temperature of the black body constant (at T), sunrays are allowed to fall on the black body through a hole in the roof of the dark room. Assuming that there is no change in the ambient temperature of the room, which of
the following statement(s) is/are correct?


(A) The quantity of radiation absorbed by the black body in unit time will increase.
(B) Since emissivity = absorptivity, hence the quantity of radiation emitted by black body in unit time will increase.
(C) Black body radiates more energy in unit time in the visible spectrum.
(D) The reflected energy in unit time by the black body remains same.

2. The smallest ketone and its next homologue are reacted with NH-2OH to form oxime.

(A) Two different oximes are formed
(B) Three different oximes are formed
(C) Two oximes are optically active
(D) All oximes are optically active

3. If 0 < θ < 2π, then the intervals of values of θ for which 2 sin^2θ − 5 sinθ + 2 > 0, is


A. (0,π/6)∪(5π/6, 2π)
B. (π/8, 5π/6)
C. (0,π/8)∪(π/6, 5π/6)
D. (41π/48, π)