Tag: ray optics and optical instruments
Questions Related to ray optics and optical instruments
Abeam of a parallel rays is brought to a focus by convex lens. If a thin concave lens of equal focal length is joined to the convex lens, the focus will
A symmetric double convex lens is cut into two equal parts along a plane perpendicular to the principal axis. If the power of the original lens is 4D, the power of the two pieces is :
The focal length of the combination of two convex lens in contact is $f$ and if they are separated by a distance, then focal length of the combination is ${f} _{1}$. The correct statement is
Two thin lens of focal lengths ${f} _{1}$ and ${f} _{2}$ are in contact. The focal length of this combination is
Two thin lenses, one of focal length $+60cm$ and the other of focal length $-20cm$ are put in contact. The combined focal length is
A convex lens of focal length $40$ cm is in contact with a concave lens of focal length $25$ cm. The power of combination is
Two lenses of power $-15D$ and $-5D$ are in contact will each other. The focal length of the combination:
There are two thin symmetrical lenses, one is converging with a refractive index $2$ and the othe other is diverging with a refractive index $1.5$. Both lenses have same radius curvature of $10 cm$. The lenses were put together and submerged in water. What is the focal length of the system of water .The refractive index of water is $\cfrac{4}{3}$
A convex lens of focal length 10 cm is in contact with a concave lens. The focal length of the combination is numerically equal to that of the concave lens. The focal length of the concave lens is :
A diverging lens of focal length $-10cm$ is moving towards right with a velocity $5m/s$. An object, placed on principal axis is moving towards left with a velocity $3m/s$. The velocity of image at the instant when the lateral magnification produced is $1/2$ is: (All velocities are with respect to ground)