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1. The unit of Stefan’s constant is
(a) Js-s(b) Jm-2 s-1 K-4(c) Jms-2(b) Jm-2 s-1 K-4
Which of the following is wrong?a) The unit of ct is same as that of λb) The unit of x is same as that of λc) The unit of 2πc/λ is same as that of 2πc/λ td) The unit of c/λ is same as that of x/λDeselect Answer
(a) dyne × cm5(b) dyne × cm4(c) dyne × cm(d) dyne × cm2Deselect Answer
5. The number of significant figures in the numbers 4.8000 × 104 and 48000.50 are respectively
(a) 5 and 6(b) 5 and 7(c) 2 and 7(d) 2 and 6
6. A cube has a side of length 2 × 10-2 m. Its volume upto correct significant figures is
(a) 1.7 × 10-6 m3.(b) 1.73 × 10-6 m3.(c) 1.7 × 10-6 m3.(d) 1.7 × 10-6 m3.
(a) 5%(b) 6%(c) 7%(d) 8%
(a) [M² L2 T-1](b) [M² L-1 T2](c) [ML2 T-1] (d) [ML-2 T1]
Deselect Answer
11. An electron at rest has a charge of 6×10-19 C. It starts moving with a velocity v=c/2, where c is the speed of light, then the new charge on it isDeselect Answer
12. Two similar and equal charges repel each other with force of 1.6 N, when paled 3 m apart. Strength of each charge is
(a) 40 μC(b) 20 μC (c) 4 μC(d) 2 μC
(a) Q2 = (Q/R), Q1= Q – (Q/R)(b) Q2 = (Q/3), Q1= Q – (2Q/3)(c) Q2 = (Q/4), Q1= Q – (3Q/4)(d) Q1 = Q2 = Q/2
(a) 1200 V/m](b) 0.04 V/m(c) 900 V/m(d) 4500 V/m
(a) will increase(b) will decrease(c) will not change(d) will first increase then decrease