NEET (NTA)National Eligibility cum Entrance Test (Medical) Physics: Questions 51  53 of 2320
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Question number: 51
» Kinematics » Average Speed and Instantaneous Velocity
Question
From the top of a multistoried building 40m tall, a boy projects a stone vertically upwards with an initial velocity of 10 ms ^{1} such that it eventually falls to the ground.
(1) After 4 s the stone will strike the ground
(2) After 2 s the stone will pass through the point from where it was projected
(3) Its velocity when it strikes the ground is 30 m/s
(4) Its velocity when it strikes the ground is 40 m/s
Choices
Choice (4)  Response  

a.  1 and 3  
b.  1 and 2  
c.  1,2 and 3  
d.  2 and 4 
Question number: 52
» Physics and Measurement » Dimensions of Physical Quantities
Question
Number of particles crossing unit area perpendicular to Xaxis in unit time is given by n =D n 2  n 1 x 2  x 1
, where n1 and n2 are number of particles per unit volume in the position x1 and x2. Find dimensions of D called as diffusion constant.
Choices
Choice (4)  Response  

a.  [M ^{0} L T ^{3}]  
b.  [M0 L2 T ^{4}]  
c.  [M ^{0} L ^{2} T ^{1}]  
d.  [M ^{0} L T ^{2}] 
Question number: 53
» Dual Nature of Matter and Radiation » Hertz and Lenard's Observations
Question
Assertion (Ꭺ)
Unit of Rydberg constant R is ml
Reason (Ꭱ)
It follows from Bohr’s formula v = R [

] the symbols have their usual meaning.
Choices
Choice (4)  Response  

a.  Ꭺ is false but Ꭱ is true  
b.  Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ  
c.  Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ  
d.  Both Ꭺ and Ꭱ are false 