Electronic flash units for cameras contain a capacitor for storing the energy used to produce the flash. In one such unit, the f
lash lasts for a time interval of 1.45×10−3 s with an average light power output of 2.20×105 W .a) If the conversion of electrical energy to light has an efficiency of 90.0 \% (the rest of the energy goes to thermal energy), how much energy must be stored in the capacitor for one flash?
b) The capacitor has a potential difference between its plates of 125 V when the stored energy equals the value calculated in part A. What is the capacitance?
b) The capacitor has a potential difference between its plates of 125 V when the stored energy equals the value calculated in part A. What is the capacitance?
1 answer:
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Answer:
1:2
Explanation:
It is given that,
Initial RMS AC voltage is 100 V and final RMS AC voltage is 200 V.
We need to find the ratio of the number of turns in the primary to the secondary for step up transformer.
For a transformer,
So,
So, the ratio of the number of turns in the primary to the secondary is 1:2.
Answer:
speed, distance and direction of motion of the object can be determined by analyzing the radio wave.
Explanation:
We know that radar operates by transmitting radio waves to a destination and these waves are comes back to the receiver station. By Considering this transmission and receiver process, we can measure the distance, velocity and path of an object's movement.
Distance can be assessed by taking following consideration, the velocity of the waves is V. It can help to assess the time made for the waves to be emitted by the radar and felt by the receiver, let the time be t.
Therefore distance can be determine as D= v*t/2,
here 2 signifies that the distance travelled by the wave in either direction ( from transmitter to receiver and vice verse)
Using the source wave frequency, speed can be computed. In a specific frequency, the radar starts sending out the frequencies and the reflected wave will have a distinct frequency. The velocity can be determine by
whereis the change in frequency and
c is the speed of light (the wave).
Direction can be determine by applying above principle. change in frequency is used to determine the direction in the following way:
When the frequency transition is very low, the object moves away from the radar and vice verse.