Q.
A rod of length 20 cm is made of metal. It expands by 0.075cm when its temperature is raised from 0oC to 100oC. Another rod of a different metal B having the same length expands by 0.045 cm for the same change in temperature. A third rod of the same length is composed of two parts, one of metal A and the other of metal B. This rod expands by 0.060 cm for the same change in temperature. The portion made of metal A has the length
see full answer
Start JEE / NEET / Foundation preparation at rupees 99/day !!
21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!
An Intiative by Sri Chaitanya
a
20 cm
b
10 cm
c
15 cm
d
18 cm
answer is B.
(Unlock A.I Detailed Solution for FREE)
Ready to Test Your Skills?
Check your Performance Today with our Free Mock Test used by Toppers!
Take Free Test
Detailed Solution
ΔL=L0αΔθRodA:0.075=20×αA×100⇒αA=752×10−6/∘CrodB:0.045=20×αB×100⇒αB=452×10−6/∘CFor composite rod: x cm of A and (20 - x) cm of B, we have0.060=xαA×100+(20−x)αB×100=x752×10−6×100+(20−x)×452×10−6×100On solving, we get x = 10 cm.
Watch 3-min video & get full concept clarity