Ray Optics and Optical Instruments Test 12

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : The focal length of the convex mirror will increase, if the mirror is placed in water.

Reason : The focal length of a convex mirror of radius R is equal to , f = R/2.

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : The image of an extended object placed perpendicular to the principal axis of a mirror, will be erect if the object is real but the image is virtual.

Reason : The image of an extended object, placed perpendicular to the principal axis of a mirror, will be erect if the object is virtual but the image is real.

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : The image of a point object situated at the centre of hemispherical lens is also at the centre.

Reason : For hemisphere Snell’s law is not valid.

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : If the rays are diverging after emerging from a lens; the lens must be concave.

Reason : The convex lens can give diverging rays.

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : The optical instruments are used to increase the size of the image of the object.

Reason : The optical instruments are used to increase the visual angle.

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : Plane mirrors may form real images.

Reason : Plane mirrors form virtual images, if the object is real.

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : The image formed by a concave mirror is certainly real if the object is virtual.

Reason : The image formed by a concave mirror is certainly virtual if the object is real.

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : An object is placed at a distance of f from a convex mirror of focal length f its image will form at infinity.

Reason : The distance of image in convex mirror can never be infinity

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion: The focal length of an equiconvex lens of radius of curvature R made of material of refractive index μ = 1.5, is R.

Reason : The focal length of the lens will be R/2.

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : The resolving power of a telescope is more if the diameter of the objective lens is more.

Reason : Objective lenses of large diameter collect more light.