Important numericals based on expansion of matter-
1. A surveyor uses a steel measuring tape that is exactly 50m long at a temperature of 200C . What is the length on the hot summer day when the temperature is 350C? coefficient of linear expansion is 1.2 x 10-5K-1. . [ans-50.009m]
2. A glass flask with volume 200cm3 is filled to the brim with mercury at 200C . How much mercury overflows when temperature of the system is raised to 1000C ?[α for glass is 0.40x 10-5K-1.and cubical exp. For mercury is 1.2x 10-5K] . Ans-2.7cm3].
3. A pendulum clock consist of an iron rod connected to a small heavy bob. If it is designed to keep correct time at 200C, how fast or slow will it go in 24 hours at 400C. ( α for iron is 1.2×10-5K-1). Ans-10.4 sec
4. When a strip made of iron (α1) and copper (α2)(α2>α1)is heated then (a)Its length doesn’t change (b)It gets twisted (c)It bends with iron on concave side (d) it bends with iron on convex side. Ans-c
5. The volume coefficient of expansion of a liquid is 7 times the volume coefficient of expansion of the vessel. The ratio of absolute and apparent expansion of the liquid is (a) 1/7 (b)7/6 (c)6/7(d)1/6.ans-b
6. The coefficient of areal expansion of a solid is 2x 10-5 0C-1. Calculate the coefficient of linear expansion.
7. A bar of iron is 10cm at 200C. At 190Cit will be ( α=11 x10 -5/0C). (a) 11 x10 -6cm longer (b) 11 x10 -6cm shorter (c) 11 x10 -5cm shorter (d) 11 x10 -5cm longer. Ans-c
8. Coefficient of volume expansion of mercury is 0.18×10-3/0C. If the density of mercury is 13.6 gm/cc . Then its density at 2000C is (a) 13.11g/cc (b)52.11g/cc (c)16.11g/cc (d) 26.11g/cc. Ans-a
9. A meter rod of silver at 00C is heated to 1000C Its length is increased by 0.19 cm then the coefficient of volume expansion of the rod is (a) 5.7 x10 -5 /C (b) 0.63 x10 -5/C (c) 1.9 x 10-5/C (d) 16.1 x10 -5/C . Ans-a
10. Ratio among coefficient of linear exp. , area and volume exp. Is (a)1:2:3 (b)3:2:1(c)4:3:2 (d) all of these . Ans-a
11. A solid ball of metal has a concentric spherical cavity within it . If the ball is heated , the volume of the cavity will (a( increase (b) decrease (c) remain same(d) all are possible. Ans-a
12. Solid expands on heating because (a) Kinetic energy of the atom increases(b)potential energy of the atom increases (c) total energy of atom increases (d) The potential energy curve is assymetric about the equilibrium distance between neighbouring atoms. Ans-d