1
JEE Main 2017 (Online) 9th April Morning Slot
+4
-1
A steel rail of length 5 m and area of cross section 40cm2 is prevented from expanding along its length while the temperature rises by 10oC. If coefficient of linear expansion and Young’s modulus of steel are 1.2×10−5 K−1 and 2×1011 Nm−2 respectively, the force developed in the rail is approximately :
A
2 $$\times$$ 107 N
B
1 $$\times$$ 105 N
C
2 $$\times$$ 109 N
D
3 $$\times$$ 10$$-$$5 N
2
JEE Main 2017 (Online) 9th April Morning Slot
+4
-1
Two tubes of radii r1 and r2, and lengths l1 and l2 , respectively, are connected in series and a liquid flows through each of them in stream line conditions. P1 and P2 are pressure differences across the two tubes.

If P2 is 4P1 and l2 is $${{{1_1}} \over 4}$$, then the radius r2 will be equal to :
A
r1
B
2r1
C
4r1
D
$${{{r_1}} \over 2}$$
3
JEE Main 2017 (Online) 8th April Morning Slot
+4
-1 In an experiment, a sphere of aluminium of mass 0.20 kg is heated upto 150oC. Immediately, it is put into water of volume 150 cc at 27oC kept in a calorimeter of water equivalent to 0.025 kg. Final temperature of the system is 40oC. The specific heat of aluminium is : (take 4.2 Joule = 1 calorie)
A
378 J/kg $$-$$oC
B
315 J/kg $$-$$oC
C
476 J/kg $$-$$oC
D
434 J/kg $$-$$oC
4
JEE Main 2017 (Online) 8th April Morning Slot
+4
-1 A compressive force, F is applied at the two ends of a long thin steel rod. It is heated, simultaneously, such that its temperature increases by $$\Delta$$T. The net change in its length is zero. Let $$\ell$$ be the length of the rod, A its area of cross-section,Y its Young’s modulus, and $$\alpha$$ its coefficient of linear expansion. Then, F is equal to :
A
$$\ell$$2 Y$$\alpha$$ $$\Delta$$T
B
$$\ell$$A Y$$\alpha$$ $$\Delta$$T
C
A Y$$\alpha$$ $$\Delta$$T
D
$${{AY} \over {\alpha \,\Delta T}}$$
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