ion No :- 8 Two simmers S1 and S2 both can swim in still water with speed 3.5 km/hr. S, starts swimming in such a way so that his net velocity is along line S2 starts along line AB and his net velocity is along AC. What should be the walking speed of S, so that both S, and S2 reach the destination
aneously. Given the river flow velocity is 3 km/hr.
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Answers
✠ The diameter of spherical mirror is called : a. focal lengthb. focal planec. radius of curvatured. aperture2. The mirror which is used by an optician while testing eye-sight of a patient isa. concave mirrorb. convex mirrorc. plane mirrord. none of these3. Which of the two laws of reflection is an extension of 'Principle of Conservation of Energy'?4. What is the exact definition of mirror,spherical mirror?5. What do you understand by rectilinear prpagation of light? Give two examples that light shows rectilinear propagation?6. What is photoelectric effect?7. One half of a convex lens is covered with a black paper. Yet this lens produces a complete image .Why?8. A coin appears to be raised when viewed obliquesly as it is dipped in water. Give reasons.9. An object of size 7 cm is placed at a distance of 12 cm from a convex lens of focal length 8 cm. Find the position,nature and size of image.10. How can we differentiate between plane,convex and concave mirror without touching them?