Class 12 Science MCQs

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Class 12 Science Online MCQs Test

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Physics Chapters For Multiple Choice Questions
Frequently Asked Questions

Access the Class 12 Science Online MCQs Test created by Web Tutors Point. The MCQs for Class 12 Science (Physics, Chemistry and Biology) are offered with the most recent exam format. By working through these problems, students can develop their critical thinking skills and do well on their board exams.

Physics Chapters For Multiple Choice Questions

Subject mastery will increase by practising the Class 12 Physics MCQs. It comprises every significant chapter on physics: Alternating Current, Current Electricity, Electric Charges and Fields, Electrostatic Potential and Capacitance, Moving Charges and Magnetism, Magnetism and Matters, Electromagnetic Induction, Electromagnetic Waves, Ray Optics and Optical Instruments, Wave Optics, Dual Nature of Radiation and Matter, Atoms, Nuclei, Semiconductor Electronics, Communication Systems

Class 12 Alternating Current

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The current in a circuit that is entirely resistive ac

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If the rms current in a 50 Hz ac circuit is 5 A, the value of the current 1/300 seconds after its value hits zero is

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220 Volt AC mains have a peak voltage of (in Volt)

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A pure inductor L receives an AC voltage that causes a current to flow through it. The inductor's current would be

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A 220 volt supply and a frequency of 50 rad/s are linked to a capacitor with a capacity of 50 microfarad. How much RMS current is there in the circuit?

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The instantaneous current in an AC series circuit reaches its maximum when the instantaneous voltage does as well. The circuit element attached to the source is going to be

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The amount of time needed for an AC with a 50 Hz frequency to complete one cycle is

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A series connection of an inductor L and a resistance R is subjected to an ac voltage. The phase difference between the applied voltage and the circuit's current is, if R and the inductive reactance are both equal to 3Ω:

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How long will it take a 50 Hz AC to go from zero to its highest value?

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For an alternating current with a frequency of π/400 Hz, the resistance of a capacitor with capacitance C is 25. C is a value of

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A 220 V, 50 Hz AC source's peak voltage is

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The rating of an ac source is 220V, 50Hz. Voltage changes from its peak value to zero in the following amount of time:

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Class 12 Electromagnetic Waves MCQs

Electromagnetic Waves Class 12 Chapter 8 Online MCQs

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What is the amplitude of electric field produced by radiation coming from a 400 W bulb at a distance of 4m? Assume efficiency of bulb to be 3.14% and assume it to the point source:

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The surface reflects the electromagnetic wave of energy U. The momentum that the electromagnetic wave then transfers to the surface is:

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Over a 120V source, a series connection of a 100 ohm resistance and a 100 ohm reactance capacitor is made. The maximum displacement current is as follows when the capacitor is 50% charged:

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From vacuum, an electromagnetic wave with frequency v=3.0 MHz travels into a dielectric medium with permittivity ϵ=16.0. Then

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Radiations from a 100 W bulb at a distance of 3 m produce an electric field with an intensity of E. The radiation from a 50 W bulb at the same distance has the following electric field intensity:

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If we want to use an oscillating charge to create electromagnetic waves with a 300 km wavelength, the oscillating charge's frequency needs to be:

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A dipole antenna emits electromagnetic waves with E0 as the amplitude of the electric field vector. The significant energy-transporting electric field E0 from the source decreases as

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Displacement current exists only when

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The pairs of vec (E) and vec (B) that can be present in a plan electromagnetic wave moving in the x direction are as follows:

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The diagnostic equipment in medicine that uses electromagnetic waves is:

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What among the following does not describe an electromagnetic wave?

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Semicircular ring of radius 0.5m is uniformly charged with a total charge of 3.14×10^−9 C. The electric filed intensity at center of this ring is

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Light with an energy flux of 20 W/cm^2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 30 cm^2, the total momentum delivered (for complete absorption) during 60 minutes is:

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The electric field created by the sun's light has an RMS value of 710 N C−1. The electromagnetic wave's overall energy density is on average:

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The speed of electromagnetic waves in a medium is 2 x 10^8 ms-1. Find the relative permeability of the medium whose relative permeability is 2.

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The carbon monoxide molecule must be split into carbon and oxygen atoms using 11 eV of energy. The relevant electromagnetic radiation's minimum frequency required to cause dissociation is:

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The electromagnetic wave will propagate in the following directions if vec E and vec B are the electric and magnetic field vectors:

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Frequently Asked Questions

What are some ways to create an alternating current?
Dynamo

Define the alternating current’s cycle time.
Alternating current’s period is the amount of time it takes to complete one cycle.

Define the alternating current’s frequency.
The number of cycles that the alternating current completes in one second is its frequency.

What happens to the inductive reactance when the frequency of the AC supply is increased?
Increases

Name a technique for producing sinusoidal alternating current.
A coil with an even magnetic field can be rotated at a constant speed to produce sinusoidal AC.

If the resistance is increased in an LCR circuit, what happens to the quality factor?
Decreases

What is an AC’s RMS value?
The square root of the mean of the squares of the instantaneous values obtained across a whole cycle is the RMS value of an AC.

What benefits do AC currents have over DC currents?
A transformer can be used to step up or step down alternating electricity.
AC can be changed into DC using electronic supply devices.
Since alternating current devices dissipate less power, they are more durable.
Transmission of electrical energy in the form of AC is more effective and inexpensive.

Define alternating current period.
The amount of time it takes to complete a cycle is called the period of alternation.

Define alternating current frequency.
The number of cycles the AC completes in a second is its frequency.

What is an AC’s mean value?
The mean or average of the instantaneous AC values calculated throughout a half-cycle is known as the mean value of AC.