Creating AM

Q. A transmitter transmits a power of 10 kW when modulation is 50%. Power of carrier wave is

1. 5 kW
2. 8.89 kW
3. 14 kW
4. 5.7 kW

Q.

What is modulation in simple words?

Q. The electric dipole potential at a large distance $r$ from the dipole falls off. The falling off the magnitude of the electric potential depends on,

1. $\frac{1}{r^2}$
2. $\frac{1}{r^3}$
3. $\frac{1}{r^4}$
4. $\frac{1}{r}$

Q. If $f_a$ and $f_f$ represent the carrier wave frequencies for amplitude and frequency modulations respectively, then

1. $f_a$ > $f_f$
2. $f_a$ < $f_f$
3. $f_a$ $\approx$ $f_f$
4. $f_a$ $\ge$ $f_f$

Q. A string, fixed at both ends, vibrates in a resonant mode with a separation of 2⋅0 cm between the consecutive nodes. For the next higher resonant frequency, this separation is reduced to 1⋅6 cm. Find the length of the string.

Q. Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio
(a) 25 : 1
(b) 5 : 1
(c) 9 : 4
(d) 625 : 1

Q. A neutral pendulum oscillates in a uniform electric field as shown in the figure. If a positive charge is given to the pendulum, then its time period

1. increases
2. first increases and then decreases
3. decreases
4. remains constant

Q. In AM, the centpercent modulation is achieved when

1. Carrier amplitude = signal amplitude
2. ${Carrieramplitude}^{-1}$ = signal amplitude
   
3. Carrier frequency = signal frequency
4. ${Carrierfrequency}^{-1}$ = signal frequency