Answer:
No, duration is not the sole reason.
Explanation:
The frequency is reciprocal of time period, so we can calculate the frequency differences between the waves as, (The frequency will not match with the actual waves frequency, since here the time for observing the wave is different)
Δf₁ = 1/5 - 1/20 = 0.15 Hz
Δf₂ = 1/200 - 1/400 = 2.5 x 10⁻³ Hz
So, the person will be able to differentiate between the waves which are farther apart. The duration of the individual tones is also important, since as the duration of the tones decreases, the number of frequencies in the wave increases (Fourier Transform), whereas a longer duration tone, has lesser number of frequencies.
One more reason is that the 200 msec and 400 msec duration waves are in frequency region of 1-5 Hz which cannot be heard by Humans.
Answer:
yes
Explanation:
because it is a diverging mirror
Answer:
The value of Q is - 8 C
Explanation:
Given;
the magnitude of first charge = 2 C
position of the first charge = 0
_ (2m) 0(+2C) +(2m)(Q)
------------------------------------------------------------------------------------
E₁ --------------------------------->
<------------------------------------------------------------------ E₂
E₁ and E₂ are equal in magnitude but opposite in direction
| E₂ | = | E₁ |

Thus, since E₂ is opposite in direction to E₁, the Q = - 8 C
Answer:
Explanation:
frequency of whistle = 1.85 x 10² = 185 Hz
frequency of beat heard = 8 beat /s . No of beat produced is equal to difference of frequencies of two sound source . Here difference is created due to Doppler effect . One of the train is moving so it will have apparent frequency which is different one from its original frequency .
When the moving train is approaching the observer , its frequency will be higher . As beat is heard at the rate of 8 beats / s , apparent frequency of approaching train will be 185 + 8 = 193 Hz .
Applying Doppler's formula of apparent frequency ,
193 = 185 x V / ( V - v ) , where V is velocity of sound and v is velocity of train .
193 V - 193 v = 185 V
193 v = 8 V
v = 8 x V / 193
= 8 x 343 / 193
= 14.21 m /s
Second possibility is that apparent velocity is less ie 185 - 8 = 177 Hz
In that case moving train will be moving away from observer . If its velocity be v
177 = 185 x V / ( V + v )
177 V + 177 v = 185 V
v = 8 x 343 / 177
= 15.50 m /s .
Because the box keeps going straight at the same speed, while the seat under it speeds up, slows down, or changes direction.