ICSE Class 12 Physics — Flashcards for Quick Revision

A: Like charges repel each other while unlike charges attract each other.

A: Attraction can occur even between a charged body and an uncharged body due to induction. Repulsion happens only when both bodies are charged with like charge, so it is the definite test.

A: Conductors are substances through which electric charge can easily flow. Metals, human body, earth, mercury, and electrolytes are conductors.

A: A concave mirror is one whose reflecting surface is towards the centre of the sphere of which the mirror is a part. It forms a real focus for parallel rays.

A: A convex mirror is one whose reflecting surface is away from the centre of the sphere of which the mirror is a part. It forms a virtual focus and always gives a virtual, erect, diminished image for a

A: The pole is the central point of the reflecting surface of the mirror. It is taken as the origin in the New Cartesian sign convention.

A: Formula: A = A · n̂ Meaning: The area vector has magnitude equal to the area and direction along the outward normal. Unit: m² for area magnitude. Quick example: For a plane surface, the vector points

A: Given: E = 20 N/C, A = 5 m², θ = 60° Formula: Φ_E = EA cosθ Step 1: cos 60° = 1/2 Step 2: Φ_E = 20 × 5 × (1/2) N·m²/C Step 3: Φ_E = 50 N·m²/C Answer: 50 N·m²/C

A: For a plane surface parallel to the field, θ = 90°. Formula: Φ_E = EA cosθ Since cos 90° = 0, the flux is 0. Physical meaning: field lines do not pass through the surface normally. Example: A surface