If P represents radiation pressure, C represents speed of light and Q represents radiation energy striking a unit area per second, then non-zero integers x, y and z such that PˣQʸ Cᶻ is dimensionless, are
Correct Answer :
x = 1, y = -1, z = 1
Solution :
The correct option is x = 1, y = -1, z = 1.
To find the values of the non-zero integers , , and such that the expression is dimensionless, we first need to determine the dimensional formula for each of the physical quantities involved.
1. Radiation Pressure ():
Pressure is defined as force per unit area.
Therefore, the dimensional formula for pressure is:
2. Radiation Energy striking a unit area per second ():
This quantity represents energy per unit area per unit time.
Therefore, the dimensional formula for is:
3. Speed of Light ():
Speed is distance traveled per unit time.
Now, we set up the requirement for the expression to be dimensionless:
Substitute the dimensional formulas into the expression:
Combining the exponents for each fundamental dimension:
By equating the powers on both sides, we get the following system of linear equations:
1) For M:
2) For L:
3) For T:
Substituting and into the third equation:
This equation is satisfied for any values of , , and as long as and .
Letting , we find:
This matches the correct option: x = 1, y = -1, z = 1.
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