A ball is dropped from a high rise platform t = 0 starting from rest. After 6 s another ball is thrown downwards from the same platform with a speed v . The two balls meet at t = 18 s. What is the value of v?
 

1.  74 m/s
2.  64 m/s
3.  84 m/s
4.  94 m/s

Subtopic:  Distance & Displacement |
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The thermo emf E (in volts) of a certain thermocouple is found to vary with Q (in C) according to equation  where Q is temperature of the hot function being kept at 0 °C. Then, the neutral temperature of the thermocouple is
 

1.  300 ° C
2.  400 ° C
3.  100 ° C
4.  200 ° C

Subtopic:  Calorimetry |
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The maximum vertical distance through which is fully dressed astronaut can jump on the earth is 0.5 m. Estimate the maximum vertical distance through which he can jump on the moon, which has a mean density 2/3 rd that of the earth and radius one quarter that of the earth.
 

1.  1.5 m
2.  3 m
3.  6 m
4.  7.5 m

Subtopic:  Gravitational Potential Energy |
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If there were a reduction in gravitational effect, which of the following forces do you think would change in some respect?
 

1.  Magnetic force
2.  Electrostatic force
3.  Viscous force
4.  Archimedes's uplift

Subtopic:  Newton's Law of Gravitation |
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Two batteries of emf 4 v and 8 V with internal resistance 1Ω and 2Ω respectively are connected to an external resistance R = 9Ω as shown in figure. The current in circuit and the potential difference between P and Q respectively will be 
1.  

 


A body at a temperature of 728 ° C and has surface area 5 cm2, radiates 300 J of energy each minute. The emissivity is 
(given Boltzmann constant )
 

1.  e = 0.18
2.  e = 0.02
3.  e = 0.2
4.  e = 0.15

Subtopic:  Stefan-Boltzmann Law |
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Considering normal incidence of ray, the equivalent refractive index of combination of two slabs shown in figure is 
 
1.  1.8
2.  1.43
3.  2
4.  None of the above

 

Subtopic:  Refraction at Plane Surface |
 54%
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Three particles having charges in the ratio of 2 : 3 : 5 produce the same point on the photographic film in Thomson experiment. Their masses are in the ratio of
 

1.  2 : 3 : 5
2.  5 : 3 : 2
3.  15 : 10 : 6
4.  3 : 5 : 2

Subtopic:  Various Atomic Models |
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