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.
Answer:
option D
Explanation:
given,
Intensity of sound = 20 dB
distance = 15 m
intensity of sound is increased to = 50 dB
distance between the sound level = ?
Using relation

L₁ = 20 dB L₂ = 50 dB r₁ = 15 m r₂ = ?





r₂ = 0.47 m
r₂ = 47 cm
hence, the correct answer is option D
Accordingly Newton's findings, astronomy and physics have industrialized
hugely over the period. Scientists now recognize that every object in the
world has a force that draws each other and the power of the force hinge on the
mass of the object. Also, Newton's Laws of Motion offer individuals a
better understanding of what is likely concerning movement. This is very helpful,
particularly in mechanics and space travel. Generally, Newton had a
huge and permanent impact on science.
Answer:
the light waves bend or REFRACT
Explanation:
“Magnets are surrounded by an invisible magnetic field that is made by the movement of electrons, the subatomic particles that circle the nucleus of an atom”
“Every magnet has both a north and a south pole. When you place the north pole of one magnet near the south pole of another magnet, they are attracted to one another. When you place like poles of two magnets near each other (north to north or south to south), they will repel each other.”