Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Concepts Of Physics MCQ Edition [Volume 1]PhysicsIntroduction to Physics

According to the theory of relativity, mass can be transformed into energy. The resulting energy E is proportional to certain powers of the mass m and the speed of light c . Determine a relation among these quantities by applying the method of dimensions.

Options

  1. AE = k m^2 c
  2. BE = k m c^2
  3. CE = k m c^2
  4. DE = k m c

Correct answer

B. E = k m c^2

Step-by-step solution

Let E = k m^a c^b , where k is a dimensionless constant. Writing the dimensional formula of each physical quantity: [E] = [M L^2 T⁻²] [m] = [M] [c] = [L T⁻¹] Substituting the dimensions in the assumed relation: [M L^2 T⁻²] = [M]^a [L T⁻¹]^b [M L^2 T⁻²] = [M^a L^b T^ -b ] Equating the powers of M , L , and T on both sides: a = 1 b = 2 -b = -2 b = 2 Substituting the values of a and b in the assumed relation: E = k m^1 c^2 E = k m c^2

Practice Introduction to Physics on Quantrex Academy →

More from Introduction to Physics

Determine the dimensions of linear momentum.Determine the dimensions of angular speed . Some of the equations involving related quantities are = ₂ - ₁ t₂ - t₁ , = ₂ - ₁ t₂ - t₁ , = F r and I = mr^2 . The symbols have standarDetermine the dimensions of angular acceleration . Some of the equations involving related quantities are = ₂ - ₁ t₂ - t₁ , = ₂ - ₁ t₂ - t₁ , = F r and I = mr^2 . The symbols have Determine the dimensions of frequency.Determine the dimensions of pressure.Determine the dimensions of torque . Some of the equations involving related quantities are = ₂ - ₁ t₂ - t₁ , = ₂ - ₁ t₂ - t₁ , = F r and I = mr^2 . The symbols have standard meaniDetermine the dimensions of moment of inertia I . Some of the equations involving related quantities are = ₂ - ₁ t₂ - t₁ , = ₂ - ₁ t₂ - t₁ , = F r and I = mr^2 . The symbols have sDetermine the dimensions of the electric field E . The relevant equations are F = qE , F = qvB , and B = ₀ I 2 a ; where F is force, q is charge, v is speed, I is current, and a is Full Introduction to Physics list All Concepts Of Physics MCQ Edition [Volume 1] PYQs