The wall will push back, in exactly the opposite direction, and with
exactly the same size force.
That's why the net force on the palm of your hand is zero, and that
in turn is the reason that your hand doesn't accelerate.
If you keep increasing the strength of your push, then eventually you
exceed the force that the wall is capable of delivering. Then the wall
crumbles and falls, your hand accelerates in the direction you're pushing,
and the crowd goes wild !
Answer:
C. microscope
Explanation:
A simple microscope is magnifying glass, an ordinary double convex lens having a short focal length that produces virtual and erect image.
Answer:
40,000N
Explanation:
Force = Acceleration × Mass
2000×20=40,000
Answer:
beam of light converges to a point A. A lens is placed in the path of the convergent beam 12 cm from P.
To find the point at which the beam converge if the lens is (a) a convex lens of focal length 20 cm, (b) a concave lens of focal length 16 cm
Solution:
As per the given criteria,
the the object is virtual and the image is real (as the lens is placed in the path of the convergent beam)
(a) lens is a convex lens with
focal length, f=20cm
object distance, u=12cm
applying the lens formula, we get
f
1
=
v
1
−
u
1
⟹
v
1
=
f
1
+
u
1
⟹
v
1
=
20
1
+
12
1
⟹
v
1
=
60
3+5
⟹v=7.5cm
Hence the image formed is real, at 7.5cm from the lens on its right side.
(b) lens is a concave lens with
focal length, f=−16cm
object distance, 12cm
applying the lens formula, we get
f
1
=
v
1
−
u
1
⟹
v
1
=
f
1
+
u
1
⟹
v
1
=
−16
1
+
12
1
⟹
v
1
=
48
−3+4
⟹v=48m
Hence the image formed is real, at 48 cm from the lens on the right side.
