Book Store

Download books and chapters from book store.
Currently only available for.
CBSE

Subject

Physics

Class

JEE Class 12

JEE Physics 2010 Exam Questions

Multiple Choice Questions

1.

STATEMENT – 1
Two particles moving in the same direction do not lose all their energy in a completely inelastic collision.
STATEMENT – 2
Principle of conservation of momentum holds true for all kinds of collisions.

  • The statement I is True, Statement II is False.

  • The statement I is True, Statement II is True; Statement II is a correct explanation for Statement I.

  • The statement I is True, Statement II is True; Statement II is not the correct explanation for Statement I.

  • Statement I is False, Statement II is


B.

The statement I is True, Statement II is True; Statement II is a correct explanation for Statement I.

264 Views

2.

A particle is moving with velocity,straight v space equals space straight k left parenthesis straight y space bold i with hat on top space plus space straight x space bold j with hat on top right parenthesis where K is a constant. The general equation for its path is

  • y = x2 + constant

  • y2 =  x + constant

  • xy = constant

  • y2 = x2 + constant


D.

y2 = x2 + constant

The velocity of the particle,straight v space equals space straight k left parenthesis straight y space bold i with hat on top space plus space straight x space bold j with hat on top right parenthesis 
rightwards double arrow space dx over dt space equals space ky comma space dy over dt space equals space kx
dy over dx space equals space dy over dt straight x dt over dx space equals space kx over ky
space ydy space equals space xdx
straight y squared space equals space straight x squared space space plus space straight C

164 Views

3.

A small particle of mass m is projected at an angle θ with the x–axis with an initial velocity v0 in the x–y plane as shown in the figure. At a time t<vosin/g, the angular momentum of the particle is

  • negative mgv subscript straight o space straight t squared space cos space straight theta space bold j with bold hat on top
  • mgv subscript 0 straight t space cos space straight theta space bold k with bold hat on top
  • negative 1 half space mgv subscript 0 straight t squared space cos space straight theta bold space bold k with bold hat on top bold space
  • 1 half space mgv subscript straight o space straight t squared space cos space straight theta space bold i with bold hat on top

C.

negative 1 half space mgv subscript 0 straight t squared space cos space straight theta bold space bold k with bold hat on top bold space

The angular momentum  of the projectile is given by,
L = m (r x v)
straight L space equals space straight m space left square bracket space straight v subscript 0 space cos space straight theta space straight t space bold i with hat on top space plus space left parenthesis straight v subscript 0 space sin space straight theta space minus space gt right parenthesis bold j with hat on top right square bracket
space space space space space space space space space space space space space straight x space left square bracket space straight v subscript straight o space cos space straight theta space straight t space bold i with hat on top space plus space left parenthesis straight v subscript 0 space sin space straight theta minus space gt right parenthesis bold j with hat on top right square bracket
equals space mv subscript 0 space cos space θt space open square brackets negative 1 half gt close square brackets bold space bold k with bold hat on top
bold space bold equals space minus 1 half space mgv subscript 0 space straight t squared space cos space straight theta bold space bold k with bold hat on top

821 Views

4.

A ball is made of a material of density ρ where ρoil < ρ < ρwater with ρoil and ρwater representing the densities of oil and water, respectively. The oil and water are immiscible. If the above ball is in equilibrium in a mixture of this oil and water, which of the following pictures represents its equilibrium position?


C.

 ρoil < ρ < ρwater 
Oil is the least dense of them, so it should settle at the top with water at the base. Now, the ball is denser than oil but less denser than water. So, it will sink through oil but will not sink in water. So, it will stay at the oil -water interface.

443 Views

5.

Two fixed frictionless inclined planes making an angle 30° and 60° with the vertical are shown in the figure. Two blocks A and B are placed on the two planes. What is the relative vertical acceleration of A with respect to B?

  • 4.9 ms-2 in horizontal direction

  • 9.8 ms-2 in vertical direction

  • zero

  • 4.9 ms-2 in vertical direction


D.

4.9 ms-2 in vertical direction

For the motion of block along inclined plane
mg sin θ =ma
a = g sin θ
where a is along the inclined plane.
The vertical component of acceleration is g sin2θ
Therefore, the relative vertical acceleration of  A with respect to B is 
g (sin260 - sin230) = g/2 = 4.9 ms-2 (in vertical direction)

453 Views

6.

For a particle in uniform circular motion, the acceleration an at straight a with rightwards arrow on top point P (R, θ) on the circle of radius R is (Here θ is measured from the x–axis)

  • negative straight v over straight R space cos space straight theta space bold i with bold hat on top space plus space straight v squared over straight R space sin space straight theta space bold j with bold hat on top
  • negative straight v over straight R space sin space straight theta space bold i with bold hat on top space plus space straight v squared over straight R space cos space straight theta space bold j with bold hat on top
  • negative straight v over straight R space cos space straight theta space bold i with bold hat on top space minus space straight v squared over straight R space sin space straight theta space bold j with bold hat on top
  • straight v squared over straight R space straight i with hat on top space plus fraction numerator begin display style straight v squared end style over denominator begin display style straight R end style end fraction space straight j with hat on top

C.

negative straight v over straight R space cos space straight theta space bold i with bold hat on top space minus space straight v squared over straight R space sin space straight theta space bold j with bold hat on top

straight a with rightwards arrow on top space equals space minus space straight V squared over straight R space cos space straight theta space straight i with hat on top space minus space straight V squared over straight R space sin space straight theta space straight j with hat on top

675 Views

7.

The figure shows the position –time (x – t) graph of one–dimensional motion of a body of mass 0.4 kg. The magnitude of each impulse is

  • 0.4 (Ns)

  • 0.8 Ns

  • 1.6 Ns

  • 0.2 Ns


B.

0.8 Ns

From the graph it is a straight line, so uniform motion. Because of impulse direction of velocity changes as can be seen from the slope of the graph.
(∴ impulse (l) = f x t
⇒ I  = mat
 space equals space fraction numerator straight m space left parenthesis straight v subscript 2 minus straight v subscript 1 right parenthesis over denominator straight t end fraction space straight t space equals space mv subscript 2 space minus space mv subscript 1
Initial velocity, v1 = 2/2 = 1 ms-1
Final velocity v2 = 2/2 = - 1 ms-1
pi  = mv1 = 0.4 N-s
pf  = mv2 = -0.4 N-s
J = pf-pi = -0.4-0.4
 = - 0.8 N-s
|J| = 0.8 N-s

438 Views

8.

A diatomic ideal gas is used in a Carnot engine as the working substance. If during the adiabatic expansion part of the cycle the volume of the gas increases from V to 32 V,the efficiency of the engine is

  • 0.5

  • 0.75

  • 0.99

  • 0.25


B.

0.75

because space PV to the power of straight gamma space equals space constant
TV to the power of straight gamma minus 1 end exponent space equals space Constant
rightwards double arrow space straight T subscript straight b straight V subscript straight b superscript straight gamma minus 1 end superscript space equals space space straight T subscript straight c straight V subscript straight c superscript straight gamma minus 1 end superscript
rightwards double arrow space straight T subscript straight b over straight V subscript straight c space equals space open parentheses straight V subscript straight c over straight V subscript 0 close parentheses to the power of straight gamma minus 1 end exponent space equals space open parentheses fraction numerator 32 space straight V over denominator straight V end fraction close parentheses to the power of 7 over 5 minus 1 end exponent
space equals space left parenthesis 2 to the power of 5 right parenthesis to the power of 2 over 5 end exponent
straight T subscript straight b space equals space 4 straight T subscript straight c space equals space 4
straight i. straight e. comma space 1 minus straight T subscript straight c over straight T subscript straight b space equals space 1 minus 1 fourth space equals space 3 over 4
282 Views

9.

The respective number of significant figures for the numbers 23.023, 0.0003 and 2.1 × 10–3 are

  • 5,1,2

  • 5,1,5

  • 5,5,2

  • 4,4,2


A.

5,1,2

228 Views

10.

A point p moves in counter -clockwise direction on a circular path as shown in the figure. The movement of P is such that it sweeps out the length s = t3 + 5, where s is metre and t is in second. The radius of the path is 20 m. The acceleration of P when t =2 s is nearly

  • 13 ms-2

  • 12 ms-2

  • 7.2 ms-2

  • 14 ms-2


D.

14 ms-2

Given that, s  =t3 +5
therefore speed v, = ds/st = 3t2
and rate of change of speed, at = dv/dt = 6t
∴ Tangential acceleration at t =2s
at = 6 x 2  = 12 ms-1
and at t = 2s, v = 3 (2)2 = 12 ms-1
∴ Centripetal acceleration, ac = v2/R = 144/20 ms-2
∴ Net acceleration  = square root of straight a subscript straight t superscript 2 space plus straight a subscript straight c superscript 2 end root space almost equal to space 14 space ms to the power of negative 2 end exponent

383 Views

1.png
curious learner
Do a good deed today
Refer a friend to Zigya

NCERT Solutions
Textbook Solutions | Additional Questions