Properties of EM Waves - NEET Physics Chapterwise MCQs & PYQs
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NEET Properties of EM Waves MCQs & PYQs
Practice NEET Properties of EM Waves Questions
Question 31:
easy
A parallel plate capacitor of capacitance $20 \mu F$ is being charged by a voltage source whose potential is changing at the rate of $3 V/s$ . The conduction current through the connecting wires, and the displacement current through the plates of the capacitor, would be, respectively.
(2019)
Conduction current is $I_c = C \frac{dV}{dt} = 20 \times 10^{-6} \times 3 = 60 \mu A$ . By Maxwell's continuity of current, the displacement current $I_d$ between the capacitor plates is equal to the conduction current in the wires, so $I_d = 60 \mu A$ .
A signal emitted by an antenna from a certain point can be received at another point of the surface in the form of
(1993)
Electromagnetic signals emitted by an antenna can propagate to another point on the Earth's surface as ground waves (traveling along the surface) or sky waves (reflected by the ionosphere). Thus, both forms are possible.
The condition under which a microwave oven heats up a food item containing water molecules most efficiently is:
(2013)
Microwave ovens heat food efficiently when the frequency of the microwaves matches the resonant frequency of water molecules, transferring energy via resonance.
If $\lambda_v$ , $\lambda_x$ and $\lambda_m$ represent the wavelengths of visible light, X-rays and microwaves respectively, then:
(2005)
The electromagnetic spectrum in order of decreasing wavelength is radio waves, microwaves, infrared, visible, ultraviolet, X-rays, gamma rays. Therefore, the relation among the given wavelengths is $\lambda_m > \lambda_v > \lambda_x$ .
Which of the following ray are not electromagnetic waves:
(2003)
X-rays, $\gamma$ -rays, and heat rays (infrared) are part of the electromagnetic spectrum. $\beta$ -rays are streams of high-energy electrons or positrons, which are particles, not electromagnetic waves.
The greenhouse effect is primarily caused by greenhouse gases in the atmosphere absorbing and re-radiating infra-red rays (heat) back towards the Earth's surface, trapping the heat.
The ozone layer in the stratosphere is biologically important because it absorbs most of the Sun's harmful ultraviolet (UV) radiation, protecting living organisms on Earth from UV-induced damage.
In the electromagnetic spectrum, cosmic rays (though mostly particles, secondary cosmic rays have EM components with extremely high energy) or high-energy gamma rays have the shortest wavelengths. Among the choices, cosmic rays have the minimum wavelength.