Answer:
b. E (about 329 Hz)
Explanation:
Given data:
Initial length of the string l1= 24 in
initial frequency f1= 247 Hz
changed length l2= 18 in
Then we have to find the changed frequency f2= ?
We already now that
frequency f ∝ 1/length of the string l
therefore,
⇒
⇒
⇒
The correct answer (sample response) is:
The image seems to be behind the mirror, but nothing is really there.
Include the following in your response:
The image appears to be behind the mirror.
If someone looks behind the mirror, there is no image there.
Answer:
The frequency of the waves depends on the distance between wave fronts - considering a front as a maximum disturbance of the wave
(Consider the waves emitted by an organ pipe: condensation and rarefactions)
The waves themselves are a fixed distance apart -
as one moves towards the source the waves received will be closer together (higher frequency)
So if the frequency received increases, the distance between the source and the observer must be decreasing
Answer:
Explained.
Explanation:
Let me explain the two cases in by one.
(1) When Person wearing a jacket, heat from his or her body is going to get trapped inside his or her jacket to keep this person warm when a thermometer is placed inside, it would indicate a higher temperature on the scale.
(2) When Jacket is Hanging in a closet, its temperature would be roughly close to room temperature and when we would place a thermometer it would not indicate any change on its scale.
Answer:
D: 0.239
Explanation:
Equation for ideal efficiency is;
η = 1 - (T_c/T_h)
We are told that;
steam comes out at 112° C. Thus, T_h = 112°C. Converting to Kelvin gives; T_h = 112 + 273 = 385 K
The one exiting into the condenser is kept at 20°C. Thus; T_c = 20 + 273 = 293 K
Thus;
η = 1 - (293/385)
η = 0.239
