Electromagnetic Waves - Online Test
Q1. Comparing X-rays and Gamma rays
Answer : Option D
Explaination / Solution:
No Explaination.
Q2. A parallel plate capacitor with circular plates of radius 1 m has a capacitance of 1 . At t = 0, it is connected for charging in series with a resistor R = 1 M across a 2V battery. Calculate the magnetic field at a point P, halfway between the centre and the periphery of the plates, after t = s. (The charge on the capacitor at time t is q (t) = CV [1 – exp (–)], where the time constant τ is equal to CR.)
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. Plane electromagnetic wave of frequency 25 MHz travels in free space along the x-direction. At a particular point in space and time, E = 6.3 j V/m. B at this point is
Answer : Option B
Explaination / Solution:
No Explaination.
Q4. The magnetic field in a plane electromagnetic wave is given by By =. Wavelength and frequency of the wave are
Answer : Option D
Explaination / Solution:
No Explaination.
Q5.
Light with an energy flux of 18 W/ falls on a nonreflecting surface at normal incidence. If the surface has an area of 20 , Average force exerted on the surface during a 30 minute time span is
Answer : Option C
Explaination / Solution:
No Explaination.
Q6. Calculate the electric and magnetic fields produced by the radiation coming from a 100 W bulb at a distance of 3 m. Assume that the efficiency of the bulb is 2.5% and it is a point source
Answer : Option B
Explaination / Solution:
No Explaination.
Q7. Figure shows a capacitor made of two circular plates each of radius 12 cm, and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15A. Capacitance and the rate of charge of potential difference between the plates are
Answer : Option D
Explaination / Solution:
No Explaination.
Q8. Figure shows a capacitor made of two circular plates each of radius 12 cm, and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15A. Displacement current across the plates is
Answer : Option B
Explaination / Solution:
No Explaination.
Q9. Applying Kirchhoff’s first rule (junction rule) valid at each plate of the capacitor
Answer : Option A
Explaination / Solution:
No Explaination.
Q10. A parallel plate capacitor made of circular plates each of radius R = 6.0 cm has a capacitance C = 100 pF. The capacitor is connected to a 230 V ac supply with a (angular) frequency of 300 rad . rms value of the conduction current is
Answer : Option C
Explaination / Solution:
No Explaination.
