1
JEE Main 2019 (Online) 12th April Evening Slot
+4
-1
One kg of water, at 20oC, heated in an electric kettle whose heating element has a mean (temperature averaged) resistance of 20 $$\Omega$$. The rms voltage in the mains is 200 V. Ignoring heat loss from the kettle, time taken for water to evaporate fully, is close to : [Specific heat of water = 4200 J/(kg oC), Latent heat of water = 2260 kJ/kg]
A
10 minutes
B
22 minutes
C
3 minutes
D
16 minutes
2
JEE Main 2019 (Online) 12th April Evening Slot
+4
-1
A diatomic gas with rigid molecules does 10 J of work when expanded at constant pressure. What would be the heat energy absorbed by the gas, in this process ?
A
35 J
B
30 J
C
25 J
D
40 J
3
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
A sample of an ideal gas is taken through the cyclic process abca as shown in the figure. The change in the internal energy of the gas along the path ca is –180 J. The gas absorbs 250 J of heat along the path ab and 60 J along the path bc. The work done by the gas along the path abc is:
A
120 J
B
130 J
C
100 J
D
140 J
4
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
At 40o C, a brass wire of 1 mm radius is hung from the ceiling. A small mass, M is hung from the free end of the wire. When the wire is cooled down from 40oC to 20oC it regains its original length of 0.2 m. The value of M is close to : (Coefficient of linear expansion and Young’s modulus of brass are 10–5 /oC and 1011 N/m 2 , respectively; g= 10 ms–2 )
A
1.5 kg
B
0.5 kg
C
9 kg
D
0.9 kg
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