Answer:
a) 3673469.39 seconds
b) 6.61×10¹⁴ m
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity = 0.12×3×10⁸ m/s
s = Displacement
a = Acceleration due to gravity = 9.8 m/s²
Equation of motion

Time taken to reach 12% of light speed is 3673469.39 seconds

The distance it would have to travel is 6.61×10¹⁴ m
Answer:
Object should be placed at a distance, u = 7.8 cm
Given:
focal length of convex lens, F = 16.5 cm
magnification, m = 1.90
Solution:
Magnification of lens, m = -
where
u = object distance
v = image distance
Now,
1.90 = 
v = - 1.90u
To calculate the object distance, u by lens maker formula given by:
u = 7.8 cm
Object should be placed at a distance of 7.8 cm on the axis of the lens to get virtual and enlarged image.