Answer:
Snell's Law states
Ni sin i = Nr sin r
Judging from the question the source of the ray is in the water (directed up)
or NI = 1 / sin 49 Ni = 1.325 deg the critical angle
From inside the pond:
Nr = 1.325 * sin 45 / 1 = 94 deg
So refraction can occur outside the pond and you do not have total internal refection.
In a string of length L, the wavelength of the n-th harmonic of the standing wave produced in the string is given by:

The length of the string in this problem is L=3.5 m, therefore the wavelength of the 1st harmonic of the standing wave is:

The wavelength of the 2nd harmonic is:

The wavelength of the 4th harmonic is:

It is not possible to find any integer n such that
, therefore the correct options are A, B and D.
Answer:
The best estimate of the depth of the well is 2.3 sec.
Explanation:
Given that,
Record time,





We need to find the best estimate of the depth of the well
According to record time,
We can write of the record time





Here, all time is nearest 2.3 sec.
So, we can say that the best estimate of the depth of the well is 2.3 sec.
Hence, The best estimate of the depth of the well is 2.3 sec.
Answer:
C
Explanation:
A Tsunami is usually the result of an earthquake under the sea
8 miles per hour
because if it is moving at 4 miles every half hour that means you have to multiply it by two to get it in miles per hour and we all know that 4 times 2 is 8 so it would be 8 miles per hour =)