- A ball rests upon a flat piece of paper on a table top. The paper is pulled horizontally but quickly towards right as shown. Relative to its initial position with respect to the table, the ball _____.
(a) remains stationary if there is no friction between the paper and the ball.
(b) moves to the left and starts rolling backwards, i.e. to the left if there is a friction between the paper and the ball.
(c) moves forward, i.e. in the direction in which the paper is pulled.- only (a)
- only (b)
- both (a) and (b)
- only (c)
- A boy throws a cricket ball from the boundary to the wicket-keeper. If the frictional force due to air cannot be ignored, the forces acting on the bal at a position X are represented by _____.
-
- A convex lens is made of 3 layers of glass of 3 different materials as in the figure. A point object is placed on its axis. The number of images of the object are
- 1
- 2
- 3
- 4
- A current I is flowing through the loop. The direction of the current and the shape of the loop are as shown in the figure. The magnetic field at the centre of the loop is
times______. (MA=R, MB=2R, ëDMA:90°) 
-
, but out of the plane of the paper. - , but into the plane of the paper.
-
, but out of the plane of the paper. - , but 1nto the plane of the paper.
-
- A point object O is kept at a distance of OP = u. The radius of curvature of the spherical surface APB is CP = R. The refractive indexes of the media are n1 and n2 which are as shown in the diagram. Then,
a) if n1 > n2, image is virtual for all values of 'u'.
b) if n2 = 2n1, image is virtual when R > u.
c) the image is real for all values of u, n1 and n2.- only a)
- a), b) and c)
- only b)
- both a) and b)
- A, B and C are the parallel sided transparent media of refractive index n1, n2 and n3 respectively. They are arranged as shown in the figure. A ray is incident at an angle q on the surface of separation of A and B which is as shown in the figure. After the refraction into the medium B, the ray grazes the surface of separation of the media B and C. Then, Sin q = ______.
-
- All capacitors used in the diagram are identical and each is of capacitance C. Then the effective capacitance between the points A and B is ______.
- C
- 3 C
- 1.5 C
- 6 C
- An electron enters the space between the plates of a charged capacitor as shown. The charge density on the plate is s. Electric intensity in the space between the plates is E. A uniform magnetic field B also exists in that space perpendicular to the direction of E.
The electron moves perpendicular to both
and 
without any change in direction.
The time taken by the electron to travel a distance l in that space is ______. -
- An ideal gas is taken via path ABCA as shown in figure. The network done in the whole cycle is
- 3P1 V1
- -3 P1 V1
- 6 P1 V1
- zero
- Assume the graph of specific binding energy versus mass number is as shown in the figure. Using this graph, select the correct choice from the following :
- Fusion of two nuclei of mass number lying in the range of 1 <A < 50 will release energy.
- Fission of the nucleus of mass number lying in the range of 100 < A < 200 will release energy when broken into two fragments.
- Fusion of two nuclei of mass number lying in the range of 100 < A < 200 will release energy.
- Fusion of two nuclei of mass number lying in the range of 51 < A < 100 will release energy.
