1
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
2
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
Two moles of helium gas is mixed with three moles of hydrogen molecules (taken to be rigid). What is the molar specific heat of mixture at constant volume ? (R = 8.3 J/mol K)
A
21.6 J/mol K
B
17.4 J/mol K
C
15.7 J/mol K
D
19.7 J/mol K
3
JEE Main 2019 (Online) 12th April Morning Slot
+4
-1
When M1 gram of ice at –10oC (specific heat = 0.5 cal g–1 oC–1 ) is added to M2 gram of water at 50C, finally no ice is left and the water is at 0°C. The value of latent heat of ice, in cal g–1 is :
A
$${{50{M_2}} \over {{M_1}}} - 5$$
B
$${{50{M_2}} \over {{M_1}}}$$
C
$${{5{M_2}} \over {{M_1}}} - 5$$
D
$${{5{M_1}} \over {{M_2}}} - 50$$
4
JEE Main 2019 (Online) 10th April Evening Slot
+4
-1
One mole of ideal gas passes through a process where pressure and volume obey the relation $$P = {P_0}\left[ {1 - {1 \over 2}{{\left( {{{{V_0}} \over V}} \right)}^2}} \right]$$. Here P0 and V0 are constants. Calculate the change in the temperature of the gas if its volume changes form V0 to 2V0
A
$${3 \over 4}{{{P_0}{V_0}} \over R}$$
B
$${1 \over 2}{{{P_0}{V_0}} \over R}$$
C
$${5 \over 4}{{{P_0}{V_0}} \over R}$$
D
$${1 \over 4}{{{P_0}{V_0}} \over R}$$
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