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AC power is transmitted from a power house at a high voltage as

a) Power cannot be transmitted at low voltage b) The rate of transmission is faster at high voltages c) A precaution against theft of... View Article

A 12 ohm resistor and an inductance of 0.21 henry are connected in series to an AC source operating at 20volts, 50 cycles/second. The phase angle between the current and the source voltage is

Solution:... View Article

A rod of weight W is supported by two parallel knife edges A and B and is in equilibrium in a horizontal position. The knives are at a distance d from each other. The centre of mass of the rod is at distance x from A. What is the normal reaction on A?

a) N_{A}=\frac{Wx}{d} b) N_{A}=\frac{W(d+x)}{d} c) N_{A}=\frac{W(d-x)}{d} d) N_{A}=\frac{Wd}{x} Solution: c) N_{A}=\frac{W(d-x)}{d}... View Article

Why does it happen? The wall of a dam is broad at its base.

Solution: Pressure of liquid increases with depth. Dam is made broader at its base to resist the heavy pressure applied by the river water.... View Article

The average momentum of the molecule in a sample of an ideal gas depends on?

a) Number of moles b) Temperature c) Volume d) None of the options Solution: d) None of the options Explanation: Average momentum is always zero... View Article

State true or false: a capacitor blocks AC but passes DC

Solution:False. Explanation: Capacitor blocks direct current but passes alternate current.... View Article

The angle of dip increases as we move from ————–

a) Equator to poles b) Poles to equator c) Dip is equal at all places d) None of these Solution: a) Equator to poles... View Article

How many photons are emitted per second by a 5 mW laser source operating at 632.8 nm?

Solution: The energy of a photon is given by the formula: E=\frac{hc}{\lambda} =\frac{(6.62*10^{-34})(3*10^{8})}{632.8*10^{-9}} = 3.14*10^{-19}J... View Article

In a mechanical refrigerator, the low temperature coils are at a temperature of −23 degree C and the compressed gas in the condenser has a temperature of 27 degree C. What is the theoretical coefficient of performance?

Solution: Given: Temperature of coil T_{2}=250K Temperature of condenser T_{1}=300K coefficient of performance of refrigerator =... View Article

The capacity of an isolated conducting sphere of radius R is proportional to

a) 2R b) R c) R^{2} d) 1/R Solution: b) R. Explanation: Since, C=4\pi \varepsilon _{0}R C\propto R... View Article

A book leans against a crate on a table. Neither is moving. Which of the following statements concerning this situation is correct?

a) The direction of the frictional force acting on the book is in the same direction as the frictional force acting on the crate. b) Although... View Article

An object of mass 3m initially at rest splits into three equal fragments, Two fragments have velocities vhat{i} and vhat{j}. What is the velocity of the third fragment?

Solution: Initial momentum of 3m mass = 0 When the object of mass 3m splits into three fragments of equal masses By the law of conservation... View Article

The process of heat transfer in which heat is transferred with actual migration of medium particles is known as

The process of heat transfer in which heat is transferred with actual migration of medium particles is known as convection. In the convection... View Article

A vehicle is moving with a velocity v on a curved road of width b and radius of curvature R. For counteracting the centrifugal force on the vehicle, the difference in elevation required in between the outer and inner edges of the road is?

a) Solution: c)... View Article

A spherical drop of capacitance 1 μF is broken into 8 drops of equal radius. What is the capacitance of each small drop?

Answer: Potential of a charged sphere is calculated using the below formula: . We know that Q = CV . Given, . After splitting, . r... View Article

A wheel whose moment of inertia is 12 kg m^2 has an initial angular velocity of 40 rad/s. A constant torque of 20 Nm acts on the wheel. The time in which the wheel is accelerated to 100 rad/s is

Solution: t=36 sec... View Article

A galvanometer has current range of 15mA and voltage range 750mV. To convert this galvanometer into an ammeter of range 25A, What is the required shunt?

Solution:... View Article

A loudspeaker that produces signals from 50 to 500 Hz is placed at the open end of a closed tube of length 1.1 m. What are the lowest and the highest frequencies that excite resonance?

Solution: For closed tube f_{n}=\frac{nv}{4L} L=1.1m, v=330m/s f_{n}=\frac{n*330}{4*1.1} For highest frequency, f_{h}=\frac{6*330}{4*1.1} =... View Article

A right-angled triangle abc, made from a metallic wire, moves at a uniform speed v in its plane as shown in the figure. A uniform magnetic field B exists in the perpendicular direction. Find the emf induced (a) in the loop abc, (b) in the segment bc, (c) in the segment ac, and (d) in the segment ab.

Solution: (a) The emf induced in the loop abc is zero. Since the components of ab are opposite to of bc they cancel each other. (b) d = Bv... View Article

A particle gets displaced by vec{Delta r}=(2hat{i}+3hat{j}+4hat{k})m under the action of a force vec{F}=(7hat{i}+4hat{j}+3hat{k}). The change in its kinetic energy is

Solution: = 14+12+12=38J... View Article