A Radiometer Has Two Square Vanes (1

question 32

Multiple Choice

A radiometer has two square vanes (1.0 cm by 1.0 cm) , attached to a light horizontal cross arm, and pivoted about a vertical axis through the center, as shown in the figure. The center of each vane is 6.0 cm from the axis. One vane is silvered and it reflects all radiant energy incident upon it. The other vane is blackened and it absorbs all incident radiant energy. An electromagnetic wave with an intensity of 0.30 kW/m² is incident normally upon the vanes. What is the torque due to radiation pressure on the vane assembly about the vertical axis? (c = 3.00 × 10⁸ m/s, μ₀ = 4π × 10^-7 T ∙ m/A, ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

• A) 2.4 × 10^-12 N ∙ m
• B) 6.0 × 10^-12 N ∙ m
• C) 1.2 × 10^-11 N ∙ m
• D) 1.8 × 10^-11 N ∙ m
• E) 2.4 × 10^-11 N ∙ m

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Definitions:

Force Field Analysis

A management technique developed by Kurt Lewin, used to identify and analyze the forces for and against a change, helping in decision making and problem solving.

Status Quo

The current state or condition of affairs, often used in the context of maintaining existing circumstances or resisting change.

Driving Forces

Describes elements or factors that contribute significantly to the pushing or motivation toward the achievement of a certain goal or change within an individual or organization.

Restraining Forces

Factors that resist or oppose the direction of change, making it difficult to move from the current state to a desired future state in organizational and personal development.