A cathode ray oscilloscope is displaying an AC signal. If one wave is completed in 20 cm along X- axis and time-base setting is 10 ms/cm, then frequency of AC signal will be:
Correct answer: B. 50 Hz
- A. 100 Hz
- B. 50 Hz
- C. 20 Hz
- D. 10 Hz
- E. 200 Hz
Explanation
The distance traveled by the wave along the X-axis in one complete cycle is the wavelength, which is given as 2 cm in the problem. The time-base setting is given as 10 ms/cm, which means that one centimeter along the X-axis represents a time of 10 ms. Therefore, the time taken for one complete cycle is:Time = (2 cm) x (10 ms/cm) = 20 msThe frequency, f, is given by the formula:f = 1/TWhere T is the time taken for one complete cycle. Substituting the value of T, we get:f = 1/20 ms = 50 HzTherefore, the frequency of the AC signal is 50 Hz. The correct answer is B.
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Progressive waves transfer energy through oscillations, with wavelength, frequency, amplitude and wave speed related by v = fλ; sound speed depends on the medium. Superposition produces interference and stationary waves in strings and organ pipes, while simple harmonic motion describes the oscillation itself and must be distinguished from wave propagation.
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