The basic relationship between wavelength

, frequency f and speed c of an electromagnetic wave is

where c is the speed of light. Substituting numbers, we find:
Answer:
It is impossible to detect underground water from the surface. Dowsing practitioners refuse to explain their secrets.
Explanation:
Answer:
Explanation:
We shall consider all movement with respect to water assuming that river is at rest or motionless .
speed of canoe = 5 m /s
in five minutes , distance between hat and canoe = 5 x 60 x 5
1500 m
This distance will be covered by man in return journey . In this case his speed is 5 m /s again considering river constant .
So this will be covered at 5 m /s
time taken = 1500 / 5 = 300 s
= 5 minutes .
so it will take 5 minutes to row back to reclaim his hat .
This question involves the concepts of general gas equation and pressure.
The force exerted by the gas on one of the walls of the container is "74.08 KN".
First, we will use the general gas equation to find out the pressure of the gas:

where,
P = Pressure of the gas = ?
V = Volume of cube = (side length)³ = (10 cm)³ = (0.1 m)³ = 0.001 m³
n = no. of moles = 3 (since molecules equal to avogadro's number make up 1 mole)
R = general gas constant = 8.314 J/mol.K
T = Absolute Temperature = 24°C + 273 = 297 K
Therefore,

P = 7407.78 KPa
Now, the force on one wall can be given as follows:

where,
A = area of one wall = (side length)² = (0.1 m)² = 0.01 m²
Therefore,

<u>F = 74.08 KN</u>
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Learn more about the general gas equation here:
brainly.com/question/24645007?referrer=searchResults