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Question

If current (I), kinetic energy (K) and charge (Q) are taken as the fundamental quantities, The dimensional representation of power will be :

The correct answer is
$[KIQ^{-1}]$

Dimensional Representation of Power using Fundamental Quantities

Understanding Dimensions

The goal is to express the dimensions of Power (P) in terms of Kinetic Energy (K), Current (I), and Charge (Q) as the fundamental quantities.

Deriving Base Dimensions

  • Kinetic Energy (K): The dimension of energy is derived from $K = \frac{1}{2}mv^2$. Thus, the dimension is $[K] = [M][L]^2[T]^{-2}$.
  • Current (I): This is taken as a fundamental quantity, so its dimension is $[I]$.
  • Charge (Q): Charge is related to current and time by $Q = It$. Thus, the dimension is $[Q] = [I][T]$.
  • Power (P): Power is the rate of change of energy, $P = \frac{Energy}{Time}$. Thus, the dimension is $[P] = \frac{[K]}{[T]}$.

Expressing Power in Fundamental Quantities

We need to express $[P] = \frac{[K]}{[T]}$ using K, I, and Q. From the dimension of charge, $[Q] = [I][T]$, we can find the dimension of time:

  • $[T] = \frac{[Q]}{[I]} = [Q][I]^{-1}$.

Now, substitute the dimension of Time into the dimension of Power:

  • $[P] = \frac{[K]}{[T]} = \frac{[K]}{[Q][I]^{-1}}$
  • $[P] = [K][Q]^{-1}[I]$
  • $[P] = [K I Q^{-1}]$

Therefore, the dimensional representation of power using K, I, and Q as fundamental quantities is $[K I Q^{-1}]$.

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Similar Questions

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Important Questions from Mechanics

  1. A person measures mass of 3 different particles as 435.42 g, 226.3 g and 0.125 g. According to the rules for arithmetic operations with significant figures, the addition of the masses of 3 particles will be.

  2. Match the LIST-I with LIST-II 

     LIST-I LIST-II
    A. Gravitational constantI.$[LT^{-2}]$
    B.Gravitational potential energyII.$[L^2T^{-2}]$
    C.Gravitational potentialIII. $[ML^2T^{-2}]$
    D.Acceleration due to gravityIV. $[M^{-1}L^3T^{-2}]$

     Choose the correct answer from the options given below:

  3. A particle is released from height S above the surface of the earth. At certain height its kinetic energy is three times its potential energy. The height from the surface of the earth and the speed of the particle at that instant are respectively.

  4. The angle of projection of a particle is measured from the vertical axis as $\phi$ and the maximum height reached by the particle is $h_m$. Here $h_m$ as function of $\phi$ can be presented as

  5. Which of the following curves possibly represent one-dimensional motion of a particle?

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