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PHYSICS, M3 EQ-Bank 10 MC

A candle is placed in front of a concave mirror, positioned beyond the centre of curvature.


Which of the following best describes the image formed by the mirror?

  1. Real, diminished and inverted
  2. Real, magnified and upright
  3. Virtual, diminished and upright
  4. Virtual, magnified and inverted
Show Answers Only

\(A\)

Show Worked Solution

When an object is placed beyond the centre of curvature of a concave mirror, the image formed is:

  • Real – because the reflected rays converge.
  • Inverted – the image appears upside down relative to the object.
  • Diminished – the image is smaller than the object.

\(\Rightarrow A\)

PHYSICS, M3 EQ-Bank 2

A laser beam is directed at a mirror with an angle of incidence of 35\(^{\circ}\), as shown in the diagram. The laser is positioned 2.5 metres horizontally in front of the mirror and 4.0 metres above the ground.
 

 

How far from the base of the mirror does the reflected beam hit the floor?   (3 marks)

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4.64 metres.

Show Worked Solution
  • By the Law of Reflection, the angle of reflection will be equal to the angle of incidence.
  • Hence the diagram below can be drawn using the information in the question.
     

\(\tan 35\) \(=\dfrac{h_1}{2.5}\)  
\(h_1\) \(=2.5 \times \tan 35=1.75\ \text{m}\)  

 
\(h_2 = 5-1.75=3.25\ \text{m}\).

\(\tan 35\) \(=\dfrac{h_2}{x}\)  
\(x\) \(=\dfrac{3.25}{\tan 35}=4.64\ \text{m}\)  

 

  • The reflected light beam strikes the floor 4.64 m from the base of the mirror.