A3-cm high object is in front of a thin lens. the object distance is 4 cm and the image distance is –8 cm. (a) what is the focal length of the lens and the kind of lens is used? (b) what is the magnification and height of the image? (c) describe the image in terms of its type, orientation and size relative to the object?

a) Focal length of the lens is 8 cm which is a convex lens

b) 6 cm

c) The lens is a convex lens and produces a virtual image which is upright and two times larger than the object.

Explanation:

u = Object distance =  4 cm

v = Image distance = -8 cm

f = Focal length

Lens Equation

a) Focal length of the lens is 8 cm which is a convex lens

Magnification

b) Height of image is 2×3 = 6 cm

Since magnification is positive the image upright

c) The lens is a convex lens and produces a virtual image which is upright and two times larger than the object.

number of electrons for neutral cl

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards