1
JEE Advanced 2015 Paper 2 Offline
MCQ (More than One Correct Answer)
+4
-2
Two spheres P and Q for equal radii have densities $$\rho$$1 and $$\rho$$2, respectively. The spheres are connected by a massless string and placed in liquids L1 and L2 of densities $$\sigma$$1 and $$\sigma$$2 and viscosities $${\eta _1}$$ and $${\eta _2}$$, respectively. They float in equilibrium with the sphere P in L1 and sphere Q in L2 and the string being taut (see figure) If sphere P along in L2 has terminal velocity vP and Q alone in L1 ha terminal velocity vQ, then

A
$${{|{v_P}|} \over {|{v_Q}|}} = {{{\eta _1}} \over {{\eta _2}}}$$
B
$${{|{v_P}|} \over {|{v_Q}|}} = {{{\eta _2}} \over {{\eta _1}}}$$
C
vP . vQ > 0
D
vP . vQ < 0
2
JEE Advanced 2014 Paper 1 Offline
MCQ (More than One Correct Answer)
+3
-0
Heater of an electric kettle is made of a wire of length L and diameter d. It takes 4 minutes to raise the temperature of 0.5 kg water by 40 K. This heater is replaced by a new heater having two wires of the same material, each of length L and diameter 2d. The way these wires are connected is given in the options. How much time in minutes will it take to raise the temperature of the same amount of water by 40 K?
A
4, if wires are in parallel
B
2, if wires are in series
C
1, if wires are in series
D
0.5, if wires are in parallel
3
JEE Advanced 2013 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-1
A solid sphere of radius R and density $$\rho$$ is attached to one end of a mass-less spring of force constant k. The other end of the spring is connected to another solid sphere of radius R and density 3$$\rho$$. The complete arrangement is placed in a liquid of density 2$$\rho$$ and is allowed to reach equilibrium. The correct statement(s) is (are)
A
The net elongation of the spring is $${{4\pi {R^3}\rho g} \over {3k}}$$
B
The net elongation of the spring is $${{8\pi {R^3}\rho g} \over {3k}}$$
C
The light sphere is partially submerged
D
The light sphere is completely submerged
4
IIT-JEE 2012 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2

A person blows into the open end of a long pipe. As a result, a high-pressure pulse of air travels down the pipe. When this pulse reaches the other end of the pipe,

A
a high-pressure pulse starts travelling up the pipe, if the other end of the pipe is open.
B
a low-pressure pulse starts travelling up the pipe, it the other end of the pipe is open.
C
a low-pressure pulse starts travelling up the pipe, if the other end of the pipe is closed.
D
a high-pressure pulse starts travelling up the pipe, if the other end of the pipe is closed.
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