WorksheetsCommunication system Physics 12 Grade
Total questions: 10
Worksheet time: 10mins
Consider the LC circuit at right. At the time shown the current has its maximum value. At this time
The charge on the capacitor has its maximum value
The magnetic field is zero
The electric field has its maximum value
The charge on the capacitor is zero
A microwave has a frequency of f1. A gamma ray has a frequency of f2. Which one has a greater speed?
The microwave
They have the same speed
The gamma ray
We need to know the wavelengths to be able to solve
Which of the following lists of electromagnetic waves is in order of increasing wavelength?
gamma rays, X-rays, radio waves, ultraviolet
microwaves, light, ultraviolet, gamma rays
ultraviolet, light, microwaves, radio waves
X-rays, gamma rays, infrared, light
Amplitude modulation is
Change in amplitude of the carrier according to modulating signal
Change in frequency of the carrier according to modulating signal
Change in amplitude of the modulating signal according to carrier signal
Change in amplitude of the carrier according to modulating signal frequency
The graph shows the frequency spectrum of an AM radio wave carrying an audio signal of a single frequency. Determine the frequency of the audio signal.
1kHz
3 kHz
5 kHz
7 kHz
An analogue signal is sampled at a frequency of 5.0 kHz. Each sample is converted into a four-bit number and transmitted as a digital signal. Show in which number equal to code 0110.
2
4
6
8
The Y-input terminals of a cathode-ray oscilloscope (c.r.o.) are connected to a supply of amplitude 5.0V and frequency 50Hz. The time-base is set at 10ms per division and the Y- gain at 5.0V per division.
Which trace is obtained?
A burst is a brief flash or pulse of light or other electromagnetic wave. Gamma- ray bursters are objects in the universe that emit pulses of gamma rays with high
energies. The frequency of the most energetic bursts has been measured at around 3∙ 1021 Hz. What is the wavelength of these gamma rays?
1∙ 10-13
2∙ 10 -13
3∙ 10 -13
4∙ 10 -13
Which of the following emits infrared radiations?
Hot iron
Ice
Freezing mixture
Wet cloth
Cross talk between fiber optic cables
Doesn’t exist
Minimal effect
Moderate effect
High effect
