Geometrical Optics - SS2 Physics Past Questions and Answers - page 3
When a converging lens is placed in contact with a diverging lens in an optical system, the combined lens system will:
Always produce a real and inverted image
Always produce a virtual and upright image
Produce a real or virtual image depending on the object distance
Produce an image with the same characteristics as the individual lenses
In an optical system where two lenses are separated by a distance, the overall magnification of the system is given by:
The product of the individual magnifications of each lens
The sum of the individual magnifications of each lens
The difference of the individual magnifications of each lens
The ratio of the individual magnifications of each lens
Which of the following is not an example of an optical system?
Telescope
Camera
Microscope
Centriscope
An object is placed 30 cm in front of a converging lens with a focal length of 15 cm. The image formed by this lens serves as the object for a diverging lens with a focal length of -20 cm. Calculate the final image distance and determine if it is a real or virtual image.
Object distance (u) = -30 cm
Focal length of converging lens (f1) = 15 cm
Focal length of diverging lens (f2) = -20 cm
To find the final image distance (v), we can use the lens formula:
1/f1 = (1/v) - (1/u1),
1/f2 = (1/v) - (1/u2).
Since the image formed by the converging lens serves as the object for the diverging lens, the object distance for the diverging lens (u2) is the negative of the image distance formed by the converging lens.
u2 = -v1.
Substituting these values into the lens formula, we have:
1/15 = (1/v) - (1/-30),
1/-20 = (1/v) - (1/-v1).
Simplifying the equations, we get:
1/v = 1/15 + 1/30,
1/v = 1/20 - 1/v1.
Now, we solve the first equation for 1/v:
1/v = 2/30 + 1/30 = 3/30,
1/v = 3/30,
v = 30/3 = 10 cm.
Substituting the value of v into the second equation, we have:
1/10 = 1/20 - 1/v1.
To isolate 1/v1, we rearrange the equation:
1/v1 = 1/20 - 1/10 = 1/20 - 2/20 = -1/20.
Taking the reciprocal of both sides, we get:
v1 = -20 cm.
Since the image distance v1 is negative, the final image formed by the diverging lens is a virtual image.
Therefore, the final image distance is -20 cm, and it is a virtual image.
What type of lens is commonly used in a compound microscope to magnify the image?
Convex lens
Concave lens
Plano-convex lens
Biconvex lens
Which of the following components in a telescope is responsible for gathering incoming light?
Eyepiece
Objective lens/mirror
Diagonal mirror
Focal length adjustment knob
The magnification of a telescope can be increased by:
Increasing the focal length of the objective lens/mirror
Decreasing the focal length of the eyepiece
Increasing the distance between the objective lens/mirror and the eyepiece
Decreasing the aperture size of the telescope
Which of the following statements is true regarding the working principle of a microscope?
Microscopes use refraction of light to magnify the image
Microscopes use reflection of light to magnify the image.
Microscopes use diffraction of light to magnify the image
Microscopes use interference of light to magnify the image.
The resolving power of a microscope is determined by:
The focal length of the eyepiece
The numerical aperture of the objective lens
The size of the specimen being observed
The distance between the eyepiece and the objective lens
Explain the working principle and applications of a compound microscope.
A compound microscope consists of two converging lenses, an objective lens, and an eyepiece. The objective lens forms a magnified real image of the object, which is further magnified by the eyepiece to produce a final virtual image. The working principle is based on the refraction of light at the lenses.
Compound microscopes have various applications in scientific research, medicine, and industry. They are widely used in biological research to observe and study microscopic organisms and cellular structures. In medicine, they are used for diagnosing diseases, examining tissue samples, and analysing blood cells. In industrial settings, they are used for quality control and inspection of small components and materials.