Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
A large cylindrical vessel contains water to a height of 10 m. It is found that the thrust acting on the curved surface is equal to that at the bottom. If atmospheric pressure can support a water column of 10 m, the radius of the vessel is
(a) 10 m (b) 15 m (c) 5 m (d) 25 m
Correct option (b) 15 mExplanation:Thrust on the curved surface 2πRh (P0 + h/2) = 300πR here as the thrust on the bottom = πR2h(P0 + h/2) = 20πR2. The atmospheric pressure in terms of column of water is 10 m. equating the two thrusts gives R = 15 m
Correct option (b) 15 m
Explanation:
Thrust on the curved surface 2πRh (P0 + h/2) = 300πR here as the thrust on the bottom = πR2h(P0 + h/2) = 20πR2. The atmospheric pressure in terms of column of water is 10 m. equating the two thrusts gives R = 15 m
See lessConsider two point masses m1 and m2 connected by alight rigid rod of length r0. The moment of inertia of the system about an axis passing through their centre of mass and perpendicular to the rigid rod is given by
Correct option (B) ur02
Correct option (B)
ur02
See lessAn isolated metallic object is charged in vacuum to a potential V0 using a suitable source, its electrostatic energy being W0. It is then disconnected from the source and immersed in a large volume of dielectric with dielectric constant K. The electrostatic energy of the sphere in the dielectric is :
(A) K2W0
(B) K W0
(C) W0/K2
(D) W0/K
Correct option (D) W0/KExplanation:U = Q2 /2C since C will become k timesSo U will become 1/k times
Correct option (D) W0/K
Explanation:
U = Q2 /2C since C will become k times
So U will become 1/k times
See lessA ball is dropped onto a horizontal surface from a height of 36 cm. After bouncing several times it comes to rest covering a total distance of 100 cm measured in a vertical direction. The percentage loss in its kinetic energy after its first impact is
(a) 36 (b) 64 (c) 53 (d) 96
Correct option (c) 53Explanation:One can write the series 100 = 36 + 2 x 36 (e2 + e4 + e6 + ..) giving e2 = 8/17 where e is the coefficient of restitution. Now, the percentage loss of kinetic energy = change in kinetic energy/original kinetic energy x 100. Note that the speed after impact is e tiRead more
Correct option (c) 53
Explanation:
One can write the series 100 = 36 + 2 x 36 (e2 + e4 + e6 + ..) giving e2 = 8/17 where e is the coefficient of restitution. Now, the percentage loss of kinetic energy = change in kinetic energy/original kinetic energy x 100. Note that the speed after impact is e times the initial speed. This gives the percentage loss as 52.94 which is almost 53 %.
See lessIt is required to decide the ratio (e1 / e2) by sum and difference method also. Four cells with different values of emf E are available. One must use a cell of emf E equal to
(a) 1.40 V (b) 2.0 V (c) 4.5 V (d) 1.08 V
Correct option (c) 4.5 VExplanation:Ratio of emfs : e1/e2 = l1/l2 Ratio of emfs by sum and difference method : e1 + e2/e1 - e2 = l1/l2 = e1/e2 = l1 + l2 /l1 - l2 The emf of the cell used in the primary circuit should be greater than (e1 + e2) E > (1.4 + 1.08)E > 2.48 volt
Correct option (c) 4.5 V
Explanation:
Ratio of emfs : e1/e2 = l1/l2
Ratio of emfs by sum and difference method : e1 + e2/e1 – e2 = l1/l2 = e1/e2 = l1 + l2 /l1 – l2
The emf of the cell used in the primary circuit should be greater than (e1 + e2) E > (1.4 + 1.08)
E > 2.48 volt
See lessRefer to the circuit given below. Output voltage V0 is measured between points a and b. Then,
(a) the peak value of V0 is 2.5 V above the minimum if the diode is assumed to be ideal
(b) the positive half cycle of the input is clipped
(c) the circuit acts as a rectifier
(d) the peak value V0 is about 3.2 V above the minimum if D is silicon diode (non-ideal)
Correct option (a) the peak value of V0 is 2.5 V above the minimum if the diode is assumed to be ideal (c) the circuit acts as a rectifier (d) the peak value V0 is about 3.2 V above the minimum if D is silicon diode (non-ideal)Explanation:The diode is reverse biased in the +ve half cycle.The diodRead more
Correct option (a) the peak value of V0 is 2.5 V above the minimum if the diode is assumed to be ideal (c) the circuit acts as a rectifier (d) the peak value V0 is about 3.2 V above the minimum if D is silicon diode (non-ideal)
Explanation:
The diode is reverse biased in the +ve half cycle.
The diode is forward biased in the –ve half cycle.
(a) If the diode is ideal, if offers infinite resistance in reverse bias, thus the entire input appears across the output. (2.5 V above the minimum)
(c) Since the negative half cycle is clipped, the circuit acts as rectifier.
(d) For a non-ideal silicon diode, threshold voltage is 0.7 V, so the output voltage will be (0.7 + 2.5 = 3.2 V) above the minimum.
See lessA thin annular metal disc of inner and outer radii R1 and R2 respectively, is freely suspended from a point on its outer circumference. The length of the corresponding equivalent simple pendulum is
Correct option (b)Explanation:Moment of inertia of annular disc about the axis under consideration can be written as m/2(R21 + R22) + mR22 Comparing the expression for the periodic time of this oscillating disc as a compound pendulum with that of a simple pendulum, we get the equivalent length.
Correct option (b)
Explanation:
Moment of inertia of annular disc about the axis under consideration can be written as m/2(R21 + R22) + mR22 Comparing the expression for the periodic time of this oscillating disc as a compound pendulum with that of a simple pendulum, we get the equivalent length.
See lessThe best material for strips marked S and S1 is
(a) Plastic (b) Aluminium (c) Cast Iron (d) Plated Brass
Correct option (d) Plated BrasExplanation:Brass is the best conducting material out of the available options. As it offers minimum resistance, the readings will be close to actual values.
Correct option (d) Plated Bras
Explanation:
Brass is the best conducting material out of the available options. As it offers minimum resistance, the readings will be close to actual values.
See lessIf the threshold of hearing is assumed to be the reference (0 dB), then the threshold of pain is taken to be 120 dB. Let the corresponding sound intensities be I0 and I respectively. Then I0/I is
(a) 120 (b) 1012 (c) 10-12 (d) 101.2
Correct option (C) 10-12Explanation:Use the definition of dB scale: 120 = 10 log10 (I/I0) , which gives (I0/I) = 10-12 .
Correct option (C) 10-12
Explanation:
Use the definition of dB scale: 120 = 10 log10 (I/I0) , which gives (I0/I) = 10-12 .
See lessThe variation of amplitude A with respect to time t is shown as
Correct option (b)Explanation:Ideal case: no damping: the amplitude remains constant. (third graph)Practical case: damping is present: amplitude decreases exponentially. Assuming the damping force is directly proportional to velocity of the bob. We can write the amplitude : A = A0 e- bt/2m Here b iRead more
Correct option (b)
Explanation:
Ideal case: no damping: the amplitude remains constant. (third graph)
Practical case: damping is present: amplitude decreases exponentially. Assuming the damping force is directly proportional to velocity of the bob. We can write the amplitude : A = A0 e- bt/2m
Here b is damping constant and m is mass of the pendulum bob.
So the correct option is (b)
See less