Multiple Choice QuestionsThe phase difference between the instantaneous velocity and acceleration of a particle executing simple harmonic motion is:
0.5π
π
0.707 π
0.707 π
A.
0.5π
The displacement equation of particle executing SHM is
x = a cos ( ωt +Φ) .. (i)
velocity, v = dx/dt = - aω sin (ωt + Φ) .. (ii)
and acceleration,
Fig (i) is a plot of eq (i) with Φ = 0. Fig (ii) shows Eq. (ii) also with Φ = 0 fig (iii) is a plot of Eq (iii) . it should be noted that in the figures the curve of v is shifted (to the left) from the curve of x by one - equate period (T/4).Similarly, the acceleration curve of A is shifted (to the left) by T/4 relative to the velocity curve of v. This implies that velocity is 90o C (0.5 π) out phase with the displacement and the acceleration is 90o C (0.5 π) out of phase with the velocity but 180o π out phase with displacement.
A vertical spring with force constant k is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically in the spring. so that the spring is compressed by a distance d. The net work done in the process is:
What is the value of inductance L for which the current is a maximum in a series LCR circuit with C =10μ F and ω = 1000 s-1
100 mH
1 mH
cannot bec calculated unless R is known
cannot bec calculated unless R is known
Three point charges +q, - 2q and +q are placed at points (x = 0, y = a, z = 0), (x = 0, y = 0, z = 0) and (x = a, y = 0, z = 0) respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are :
along +y direction
qa along the line joining pointsqa along the line joining points
(x = 0, y = a, z = 0) and (x = a, y = a, z = 0)
qa along the line joining points
(x = 0, y = a, z = 0) and (x = a, y = a, z = 0)
The resistance of an ammeter is 13 Ω and its scale is graduated for a current up to 100 A. After an additional shunt has been connected to this ammeter it becomes possible to measure currents up to 750 A by this meter. The value of shunt resistance is.
20 Ω
2 Ω
0.2 Ω
0.2 Ω
Under the influence of a uniform magnetic field. a charged particle is moving in a circle of radius R with constant speed v. The time period of the motion.
depends on v and not on R
depends on both R and v
is independent of both R and v
is independent of both R and v
The primary and secondary coil of a transformer have 50 and 1500 turns respectively. If the magnetic flux Φ linked with the primary coil is given Φ = Φo +4t, where Φ is in weber, t is time is second and Φo is a constant the output voltage across the secondary coil is:
90 V
120 V
220 V
220 V
Two condensers, one of capacity C and the of capacity C/2, are connected to a V volt battery, as shown.
This work done in charging fully both the condensers is:
2 CV2
CV2/4
3CV2/4
3CV2/4
A transforner is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 A, the efficiency of the transformer is approximately:
30%
50 %
90 %
90 %
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