What happens when intensity is doubled?
Any change in the energy of the photons will not change the intensity. So if intensity is doubled, the no. of photons incident on the surface will be doubled and as a result more photoelectrons will be ejected.
What is the value of maximum usable frequency when the incident angle is 60 and the critical frequency is 4.5 MHz?
7. What is the value of maximum usable frequency when the incident angle is 60° and the critical frequency is 4.5MHz? Explanation: MUFfMUF = fcsecθi = 4.5MHz ×sec60=9MHz.
What do you mean by maximum usable frequency?
In radio transmission maximum usable frequency (MUF) is the highest radio frequency that can be used for transmission between two points via reflection from the ionosphere (skywave or “skip” propagation) at a specified time, independent of transmitter power. Typically the MUF is a predicted number.
What is the maximum usable frequency for E layer of atmosphere?
“At incidence, generally frequencies below 10 MHz are reflected but with active events frequencies up to 50 MHz and higher may also be reflected by the E-layer.”
What is the difference between critical frequency and maximum usable frequency?
As mentioned in the MUF formula, it depends on critical frequency and angle of incidence. MUF (Maximum Usable Frequency) is the maximum frequency which can be reflected for given distance of transmission. MUF is usually 3 to 4 times of critical frequency.
What is meant by critical frequency?
Critical frequency is the highest magnitude of frequency above which the waves penetrate the ionosphere and below which the waves are reflected back from the ionosphere. It is denoted by “fc”. Its value is not fixed and it depends upon the electron density of the ionosphere.
What is the formula of critical frequency?
since Hi/W=1/4. In the natural convection case, the critical frequency is approximately 0.255 and in the mixed convection case, for Re = 100, it is found approximately 0.18, both in non-dimensional values. A simple calculation, for Re = 100 and Pr = 0.733, eq.
Is critical frequency and cutoff frequency same?
The cutoff frequency is known as a frequency creating a boundary between pass and stop band. If the signal frequency is more than the cutoff frequency for a high pass filter then it will cause the signal to pass. The cutoff frequency equation for first order high pass filter is same as low pass filter.
What is 3dB frequency?
3db is the power level, its the frequency at which the power is at 3db below the maximum value and 3db means in normal unit its half the maximum power so 3db frequency means the frequency at which the power is half the maximum value so its decided the cuttoff frequency.
What is 3 dB cutoff frequency?
The frequency at which the power level of the signal decreases by 3 dB from its maximum value is called the 3 dB bandwidth. A 3 dB decrease in power means the signal power becomes half of its maximum value.
Why cutoff frequency is called down frequency?
This frequency fc is called the cutoff frequency because, for frequencies lower than this, no power will be transmitted down the horn, i.e., the impedance at all positions along the horn is purely reactive.