What is the object distance of a concave mirror?
| focal length | object distance | |
|---|---|---|
| concave mirror | positive | positive |
| convex mirror | negative | positive |
| converging lens | positive | positive |
| diverging lens | negative | positive |
Who gave the lens formula?
Thin Lens Formula — from Eric Weisstein’s World of Physics. in 1693 (Steinhaus 1983, p. 301).
Is object distance positive or negative?
object distance is always negative for all the lens & mirrors. image distance depends on object distance in case of concave mirror and convex lens. ‘v’ is always positive for convex mirror & concave lens.
What is the formula of concave lens?
Lens equation – Concave lens and examples
| F | = | Principal focal length |
|---|---|---|
| do | = | Object distance |
| di | = | Image distance |
What is V and U in mirror formula?
It is also known as a mirror formula. In a spherical mirror: The distance between the object and the pole of the mirror is called the object distance(u). The distance between the image and the pole of the mirror is called Image distance(v).
At what distance does a concave mirror focal length 20cm?
Thus, the distance of the object from the mirror is equal to 10cm. Hence, the correct answer is option C.
At what distance from a concave lens of focal length 20cm is 6 cm?
Answer. Thus, object should be placed at 60 from the lens .
Where an object should be placed before a concave mirror of focal length 20 cm so that a real image is formed at a distance of 60 cm from it?
where an object should be placed before a concave mirror of focal length 20cm so that a real image is formed at a distance of 60cm from it? Object Distance (u) = ? So, the object must be placed between Centre of Curvature and Focus at the distance of 30 cm from the mirror.
At what distance an object is kept from a concave mirror of focal length 20 cm such a way that it forms two times magnified image?
Answer Expert Verified magnification “m”=-2times. 40+2u=-20. so if you object be placed at the distance of 30 cm then the two times magnified image will be obtain.
Where should an object be placed in front of a concave mirror of focal length 20 cm?
Where should an object be placed in front of a concave mirror of focal length 20 cm so as to obtain a two time magnified real image? [2011] Ans: 30 cm.
What will be the position of an image formed if an object is kept at 10 cm in front of a concave mirror of focal length 20 cm?
hence, image position is the 20cm right side from the pole of the concave mirror as shown in the diagram. The image is straight and bigger than the object.
Where should the object be placed near a convex lens of focal length 20 cm to get a two times magnified real image?
Object should be placed at 15cm in front of the lens.
How far from a convex lens of focal length 20 cm would you place an object to get an image enlarged 3 times?
u= -2 x 20/3 = -40/3 cm. u= -2 x 20/3 = -40/3 cm. Answer: Between the centre of the curvature and its focus, if the image is real.
What is the power of a lens with a focal length of 20 cm?
20 CM in metres= 20/100m=1/5 metres. power of a lens= 1/1/1/5=5 dioptres……..
What is the power of a lens if its focal length is 50 cm?
Power of a lens is always reciprocal to the focal length. So, aconvex lens with 50cm focal length has a power of (1/0.5) Dioptre(D) or 2D. Since, a convex lens is a converging lens, thepower of the convex lens is +2D………
What is the power of lens of focal length?
The power of a lens is defined as the reciprocal of the focal length. Lens power is measured in dioptres (D). Converging (convex ) lenses have positive focal lengths, so they also have positive power values. Diverging (concave ) lenses have negative focal lengths, so they also have negative power values.
What is the power of a lens of focal length 10 cm?
Now, putting this value of focal length in the formula for the power of a lens. Thus, the powerof this convex lens is +10 dioptres which is also written as +10D.
What is the relation between power and focal length?
The power of a lens is defined as the reciprocal of its focal length in meters, or D = 1/f, where D is the power in diopters and f is the focal length in meters. Lens surface power can be found with the index of refraction and radius of curvature.
Which converging lens has the greatest power?
The convex lens of smaller focal length (= 20 cm) has greater power since focal length is reciprocal of power.
Is convex lens positive or negative?