For the plane electromagnetic wave given by E=E0sin(ωt−kx) and B=B0sin(ωt−kx), the ratio of average electric energy density to average magnetic energy density is
Physicselectromagnetic-waves2023easy
The energy density associated with electric field E and magnetic field B of an electromagnetic wave in free space is given by (ϵ0− permittivity of free space, μ0− permeability of free space)
Physicswork-power-and-energy2023easy
Identify the correct statements from the following :
A. Work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket is negative.
B. Work done by gravitational force in lifting a bucket out of a well by a rope tied to the bucket is negative.
C. Work done by friction on a body sliding down an inclined plane is positive.
D. Work done by an applied force on a body moving on a rough horizontal plane with uniform velocity is zero.
E. Work done by the air resistance on an oscillating pendulum is negative.
Choose the correct answer from the options given below :
Physicswork-power-and-energy2023easy
A stone is projected at angle 30∘ to the horizontal. The ratio of kinetic energy of the stone at point of projection to its kinetic energy at the highest point of flight will be -
Physicswork-power-and-energy2023medium
The ratio of powers of two motors is x+13x, that are capable of raising 300kg water in 5 minutes and 50kg water in 2 minutes respectively from a well of 100m deep. The value of x will be
Physicswork-power-and-energy2023easy
Two bodies are having kinetic energies in the ratio 16 : 9. If they have same linear momentum, the ratio of their masses respectively is :
Physicswork-power-and-energy2023easy
Given below are two statements:
Statement I : A truck and a car moving with same kinetic energy are brought to rest by applying breaks which provide equal retarding forces. Both come to rest in equal distance.
Statement II : A car moving towards east takes a turn and moves towards north, the speed remains unchanged. The acceleration of the car is zero.
In the light of given statements, choose the most appropriate answer from the options given below
Physicswork-power-and-energy2023medium
A bullet of mass 0.1kg moving horizontally with speed 400ms−1 hits a wooden block of mass 3.9kg kept on a horizontal rough surface. The bullet gets embedded into the block and moves 20m before coming to rest. The coefficient of friction between the block and the surface is __________.
(Given g=10m/s2 )
Physicsalternating-current2023easy
An alternating voltage source V=260sin(628t ) is connected across a pure inductor of 5mH Inductive reactance in the circuit is :
Physicsalternating-current2023easy
Match List - I with List - II :
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List I
List II
A.
AC generator
I.
Presence of both L and C
B.
Transformer
II.
Electromagnetic Induction
C.
Resonance phenomenon to occur
III.
Quality factor
D.
Sharpness of resonance
IV.
Mutual Induction
Choose the correct answer from the options given below :
Physicsalternating-current2023easy
If R,XL, and XC represent resistance, inductive reactance and capacitive reactance. Then which of the following is dimensionless :
Physicsalternating-current2023medium
In the given circuit, rms value of current (Irms) through the resistor $R$ is:
Physicsalternating-current2023easy
In a series LR circuit with XL=R, power factor P1. If a capacitor of capacitance C with XC=XL is added to the circuit the power factor becomes P2. The ratio of P1 to P2 will be :
Physicsalternating-current2023medium
For the given figures, choose the correct options :
Physicsalternating-current2023easy
In an LC oscillator, if values of inductance and capacitance become twice and eight times, respectively, then the resonant frequency of oscillator becomes x times its initial resonant frequency ω0. The value of x is :
Physicsalternating-current2023easy
Given below are two statements:
Statement I : An AC circuit undergoes electrical resonance if it contains either a capacitor or an inductor.
Statement II : An AC circuit containing a pure capacitor or a pure inductor consumes high power due to its non-zero power factor.
In the light of above statements, choose the correct answer form the options given below:
Physicsalternating-current2023easy
Given below are two statements:
Statement I : When the frequency of an a.c source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreases.
Statement II : In a series LCR circuit, the value of power factor at resonance is one.
In the light of given statements, choose the most appropriate answer from the options given below.
Physicsalternating-current2023easy
As per the given graph, choose the correct representation for curve A and curve B.
Where XC= reactance of pure capacitive circuit connected with A.C. source
XL= reactance of pure inductive circuit connected with A.C. source
R = impedance of pure resistive circuit connected with A.C. source.
Z= Impedance of the LCR series circuit }
Physicsalternating-current2023easy
Given below are two statements:
Statement I : Maximum power is dissipated in a circuit containing an inductor, a capacitor and a resistor connected in series with an AC source, when resonance occurs
Statement II : Maximum power is dissipated in a circuit containing pure resistor due to zero phase difference between current and voltage.
In the light of the above statements, choose the correct answer from the options given below:
Physicsalternating-current2023medium
A capacitor of capacitance 150.0μF is connected to an alternating source of emf given by E=36sin(120πt)V. The maximum value of current in the circuit is approximately equal to :