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Cp and Cv are specific heats at constant pressure and constant volume, respectively. It is observed that Cp − Cv =a for hydrogen gas Cp − Cv =b for nitrogen gas. The correct relation between a and b is :

In a system, Cp is the amount of heat energy released or absorbed by a unit mass of the substance with the change in temperature at a constant... View Article

With what minimum acceleration can a fireman slide down a rope whose breaking strength is two third of his weight?

We've been given a rope with a breaking strength equal to two-thirds of the foreman sliding down on it; hence, the rope has a tension equal to... View Article

The distance between an object and a screen is 100cm. A lens produces an image on the screen when the lens is placed at either of the positions 40cm apart. The power of the lens is nearly

The central part of a convex lens is thicker than the edges. Because of its converging nature, this lens is called a converging lens. When light... View Article

An AC voltage source of variable angular frequency ωand fixed amplitude V0 is connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When ω is increased A. the bulb glows dimmer B. the bulb glows brighter C. total impedance of the circuit is unchanged D. total impedance of the circuit increases.

In an AC circuit, the amplitudes of the voltages across the components and the current in the circuit are treated as vectors. The phase... View Article

The amplitude of a particle executing S.H.M. is 4cm . At the mean position the speed of the particle is 16cms⁻¹ . The distance of the particle from the mean position at which the speed of the particle becomes 8√3cms⁻¹ , will be:

Assume that the amplitude of S.H.M. be A , at mean position the velocity of the particle is maximum hence, let velocity be Vmax , The velocity... View Article

The resistance if a wire is ‘R’ ohm. If it is melted and stretched to ‘n’ times its original length, its new resistance will be:

It is given that there is a wire of radius r, length l1 having a resistance R. Now this wire is said to be extended to a new length l2 , which... View Article

An inductor of inductance L= 400mH and resistors R1=2Ω and R2=2Ω are connected to a battery of emf 12V . The internal resistance of the battery is negligible. The switch S is closed at t=0. The potential drop across L as a function of time is:

oltage across the inductor in the circuit is proportional to the rate of current flow through the inductor. For this first calculate the current... View Article

The electric field part of an electromagnetic wave in a medium is represented by Ex = 0 Ey=2.5N/C cos[(2π × 106rad/s)t−(π × 10−2rad/mx)]

We know that the standard equation of electromagnetic wave is given by: Ey = E0cos(wt−kx) The equation that is given is: Ey=2.5N/C cos[(2π ×... View Article

Two forces, each of magnitude F have a resultant of magnitude F . What is the angle between the two forces?

The push or pull that is exerted to an item causes the body to accelerate. The force, as we all know, is a vector. As a consequence, we'll employ... View Article

To an evacuated vessel with a movable piston under a total pressure of 1 atm, 0.1 mol of He and an unknown compound (vapour pressure 0.68 atm at 0℃) are introduced. Considering the ideal gas behaviour, the total volume (in litre) of the gases at 0℃ is close to:

For a better understanding of the Ideal Gas Equation, let us mention the four gas variables and one constant. Pressure (P), Volume (V), Number of... View Article

A planet revolves around the sun in an elliptical orbit. If Vp and Va are the velocities of the planet at the perigee and apogee respectively, then the eccentricity of the elliptical orbit is given by:

Eccentricity of an ellipse is defined as the ratio of the distance between the centre of the ellipse and each focus to the length of the... View Article

Why are alloys used for making standard resistance coils?

Answer: Standard resistance coils are made from alloys, which have a high resistivity value and a low temperature coefficient of resistivity.... View Article

An ac source of angular frequency ω is fed across a resistor R and a capacitor C in series. The current registered is I . If now the frequency of the source is changed to ω/3 (but maintaining the same voltage), the current in the circuit is found to be halved. The ratio of the reactance to resistance at the original frequency ω is given as √ x/5 . Find x .

The root-mean-square current Irms in the RC circuit is given by Irms = Vrms/√R2 +X2C…… (1) Here, Vrms is the root-mean-square voltage, R is the... View Article

What is inductive resistance formula?

The resistance of an inductive circuit is known as inductive reactance or simply reactance. Because it differs somewhat from the resistance given... View Article

A stone is dropped from a height h. It hits the ground with a certain momentum p. If the stone is dropped from a height 100% more than the previous height, the momentum when it hits the ground will change by A) 68% B) 41% C) 200% D) 100%

answer: (B) 41% A stone is dropped from a height of h in the first scenario. We may deduce from the equations of motion that the velocity of... View Article

A particle of charge q and mass m enters normally (at point P) in a region of the magnetic field with speed v. It comes out normally from Q after time T as shown in fig. The magnetic field Bis present only in the region of radius R and is uniform. Initial and final velocities are along the radial direction and they are perpendicular to each other. For this to happen, which of the following expression(s) is/are correct?

When a charged particle in motion is exposed to a magnetic field that is perpendicular to its direction of travel, we know that the particle will... View Article

The equivalent resistance between point A and B is: a) 32.5Ω b) 22.5Ω. c)2.5ΩD. d) 2.5Ω

Answer: (b) 22.5 As you can see in the equivalent circuit diagram, it depicts a series combinations of resistances in the circuit. 15Ω, 10Ω,... View Article

Two steel wires having same length are suspended from a ceiling under the same load. If the ratio of their energy stored per unit volume is 1 : 4, the ratio of their diameters is:

Energy density =du/dv, where u is Energy v is volume ⇒ du/dv = F2/2A2y (stress = F/A) ⇒ du/dv ∝ 1/A2 ⇒ du/dv ∝ 1/d4 (∵Area = π/4 × d4) A2... View Article

What is the strength of the magnetic field around a thin, long straight conductor?

A Magnetic field is generally interpreted as a region where the force of magnetism acts. This force of magnetism is mainly produced as a result... View Article

A convex lens and convex mirror are placed co axially and separated by distance d. The focal length of both is 20cm each. A point object is placed at a distance 30cm from the lens. Then the value of d so that image on the object itself is

Given parameters are The focal length of the convex lens is f1=20cm. The focal length of the convex mirror is, f2=20cm The distance of the... View Article

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