Answer:
i) 21 cm
ii) At infinity behind the lens.
iii) A virtual, upright, enlarged image behind the object
Explanation:
First identify,
object distance (u) = 42 cm (distance between object and lens, 50 cm - 8 cm)
image distance (v) = 42 cm (distance between image and lens, 92 cm - 50 cm)
The lens formula,

Then applying the new Cartesian sign convention to it,

Where f is (-), u is (+) and v is (-) in all 3 cases. (If not values with signs have to considered, this method that need will not arise)
Substituting values you get,
i) 
f = 21 cm
ii) u =21 cm, f = 21 cm v = ?
Substituting in same equation
v ⇒ ∞ and image will form behind the lens
iii) Now the object will be within the focal length of the lens. So like in the attachment, a virtual, upright, enlarged image behind the object.
Answer:
Smaller and upside down
Explanation:
To answer the question, we must recognise that the characteristics of the image formed by a convex lens depends on the position of the object from the lens.
From the diagram given in the question above, the following data were obtained:
1. The image is smaller than the object.
2. The image is inverted i.e upside down.
3. The image is closer to the lens
4. The image between 2f and f
Now, considering the options given in question above, the correct answer to the question is:
The image is smaller and upside down.
Answer:
P.E = 980 Joules
Explanation:
Given the following data;
Mass = 20 kg
Height = 5m
Acceleration due to gravity = 9.8 m/s²
To find the potential energy stored in the block;
Mathematically, potential energy is given by the formula;

Where,
P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
Substituting into the equation, we have;

P.E = 980 Joules
The portion of the flux leaves the curved surface of the cylinder is 60%.
<h3 /><h3>What are electrons?</h3>
The electrons are the spinning objects around the nucleus of the atom of the element in an orbit.
If a point charge is located at the center of a cylinder and the electric flux leaving one end of the cylinder is 20% of the total flux leaving the cylinder.
If 20% of the flux leave from one end, then another 20% will leave from another end.
So, the net flux through curved surface is
100 -20 -20 = 60%
Thus, the total flux leaves the curved surface of the cylinder is 60%
Learn more about electrons.
brainly.com/question/1255220
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Answer:
2. 200N
3.50kg
4.700N
Explanation:
Weight is another word for the force of gravity
Weight is a force that acts at all times on all objects near Earth.
F=m*g
where g=acceleration due to gravity
2. due to the gravitational fields of the earth , assume gravitational acceleration=10m/s2
F=20*10= 200N
3.same as above
mass=Force/gravitational acceleration
mass=500/10 = 50kg
4.force=mass*gravitational acceleration
force=70*10=700N