(c) Both 1 and 2
           (d) Neither 1 nor 2
Ans : (c)
279. Consider the following statements:
                1) A flute of smaller length produces waves of lower frequency.
                2) Sound travels in rocks in the form of longitudinal elastic waves only.
           Which of the statements given above is/are correct? [IAS 2007]
           (a)  1 only
           (b)  2 only
           (c)  Both 1and 2
           (d)  Neither 1 nor 2
Ans : (d)
280. Four wires of same material and of dimensions as under are stretched by a load of same magnitude separately. Which one of them
     will be elongated maximum? [IAS 2007]
           (a) Wire of 1m length and 2 mm diameter
           (b) Wire of 2 m length and 2 mm diameter
           (c) Wire of 3m length and 1.5mm diameter
           (d) Wire of 1m length and 1mm diameter
Ans : (c)
281. Three identical vessels A, Band Care filled with water, mercury and kerosene respectively up to an equal height. The three vessels
     are provided with identical taps at the bottom of the vessels. If the three taps are opened simultaneously, then which vessel is
     emptied first? [lAS 2007]
           (a) Vessel B
           (b) All the vessels A. Band C will be emptied simultaneously
           (c) Vessel A
           (d) Vessel C
Ans : (b)
282. In which one among the following is the speed of sound maximum? [IAS 2006]
           (a) Air at 0°C
           (b) Air at 100°C
           (c) Water
           (d) Wood
Ans : (c)
283. What does the term "Dolby B", or "Dolby C" printed on tape recorders and other sound system refer to? [IAS 2006]
           (a) Frequency modulated system
           (b) Amplitude modulated system
           (c) Noise reduction circuit
           (d) Both DC and AC power can be used
Ans : (c)
284. Which one of the following is printed on a commonly used fluorescent tube light? [lAS 2006]
           (a) 220 k
           (b) 273 k
           (c) 6500 k
           (d) 9000 k