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10th Class Science Light - Reflection and Refraction Question Bank Light

  • question_answer
    The diameter of the moon is about 3500 km. What will be the diameter of the image formed by a concave mirror of radius 3m? Assume that the distance of the moon is about \[\text{3}\text{.5 }\times \text{ 1}0\text{5}\]km.

    A)  5 mm                   

    B)         10 mm

    C)  15 mm                  

    D)         20 mm

    Correct Answer: C

    Solution :

     Here, angle subtended by moon                 \[=\frac{3500}{3\cdot 5\times {{10}^{5}}}radians\] Also, focal length of the mirror,                 \[f=R/2=1\cdot 5\,\,m\]                    \[=1.5\times {{10}^{3}}mm\] \[\therefore \]  \[I=f\theta =1\cdot 5\times {{10}^{3}}\times \frac{3500}{3\cdot 5\times {{10}^{6}}}\] \[=15\,\,cm\]


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