Related InterviewSolutions

• In a region of free space the electric at some instant of time to `vecE=(80hati+32hatj-64hatk)` and the magnetic field is `vecB=(0.2hati+0.08hatj-0.29hatk)mu` T. The pointing vector for these field is:A. `-11.52hati+28.8hatj`B. `-28.8hati+11.52hatj`C. `28.8hatj-11.52hatj`D. `11.52hati-28.8hatj`
• A charged particle oscillates about its mean equilibrium position with a frequency of `10^(9)` Hz. The frequency of electromagnetic waves produced by the oscillator isA. `10^(6)Hz`B. `10^(7)Hz`C. `10^(8)Hz`D. `10^(9)Hz`
• If you find closed loops of `vecB` in a region in space, does it necessarily mean that actual charges are flowing across the area bounded by the loops ?
• What oscillates in e.m. waves? Give two examples of e.m. waves.
• The `21 cm` radio wave emitted by hydrogen in interstellar space is due to the interaction called the hyperfine interaction is atomic hydrogen. The energy of the emitted wave is nearlyA. `10^(-7)` jouleB. `1` jouleC. `7xx10^(-8)` jouleD. `10^(-24)` joule
• In a plane electromagnetic wave the electric field oscillates sinusoidally at a frequency `3xx10^10Hz` and amplitude `50V//m`. (a) What is the wavelength of the wave? (b) What is the amplitude of the oscillating magnetic field?
• The velocity of light in vacuum can be changed by changingA. frequencyB. amplitudeC. wavelengthD. none of these
• One cannot cannot see through fog, becauseA. for absorbs the lightB. light suffers total reflection at dropletsC. refractive index of the fog is infinityD. light is scattered by droplets
• optical and radio telecopes are build on ground but X-ray astronomy is possible only from satellites or biting the earth. Explain why?
• If a capacitor of `2.0muF` is charged to 20V and then suddenly short-circuited by a coil of negligible resistance and of inductance `8.0muH` Calculate the maximum amplitude and the frequency of the resulting current oscillations.