What is meant by focal length of convex lens?
The distance between the convex lens or a concave mirror and the focal point of a lens or mirror is called the focal length. It is the point where parallel rays of light meet or converge. The focal length varies with the sign (positive or negative) depending upon the nature of the lens and mirror(concave or convex).
What is meant by focal length of a lens?
The focal length of a lens is determined when the lens is focused at infinity. Lens focal length tells us the angle of view—how much of the scene will be captured—and the magnification—how large individual elements will be. The longer the focal length, the narrower the angle of view and the higher the magnification.
What is the focal length of convex mirror lens?
The distance from the lens to the focal point is called the focal length. For diverging or convex mirrors, the focal length is always positive. For a converging or concave mirror, the focal length is always negative. The focal length of a convex mirror is half of its radius of curvature.
What is focal length of lens Class 10?
Focal length of a lens is the distance between centre of lens and focal point . Focal point is a point on principal axis , at which light rays parallel to principal axis meet after refraction through lens or seem to meet after refraction .
What is focal length of concave lens?
The distance between the pole and the principal focus is called the focal length (f) of the lens. The given focal length of the concave lens is f = -2 m. It is negative because a concave lens always has a negative focal length.
What is focal length of a lens Class 12?
The Focal length of a lens is half of its radius of curvature. We usually denote the centre of curvature of a lens with the term 2Finstead of denoting it by C. Where u is the distance of the object from the lens, v is the distance of image formed from the lens, and f is the focal length of the lens.
What is the focal length of a concave lens?
Answer: According to the sign convention, the focal length of a concave lens is always negative.
What is focal length of concave and convex lens?
Viva Questions
| Convex lens | Concave lens |
|---|---|
| The focal length is positive | The focal length is negative |
| Image obtained can be either real or virtual | Image obtained is always virtual |
| The light rays are converged towards the principal axis | The light rays diverge away from the principal axis |
What is the focal length of a lens Class 12?
Focal length of a spherical lens is the distance between optical centre and focus of the lens. The Focal length of a lens is half of its radius of curvature.
What is convex lens Class 12?
This type of lens is thicker at the center and thinner at the edges. An optical lens is generally made up of two spherical surfaces. If those surfaces are bent outwards, the lens is called a biconvex lens or simply convex lens.
What is the focal length of a concave and convex lens?
Concave and convex lenses, each has the same focal length 20 cm. and they are put in contact to form a combination lens.
What is focal length of concave mirror?
Focal length is the distance between the center of a convex lens or a concave mirror and the focal point of the lens or mirror the point where parallel rays of light meet, or converge.
What is convex lens class 7th?
Convex lens are thicker in middle than the edges whereas concave lens are thinner at the middle than at the edges. Lenses are transparent and light can pass through them. Convex lens are also called convergent as they concentrate (bend inward) the light falling on it.
What is the focal length of concave lens?
What is the focal length of convex lens give reason to justify your answer?
3 as when an object is placed at a distance from the convex lens its image is formed on the other side of the lens at the same distance from the lens. So, the radius of curvature is 40 cm. Thus, focal length is half the radius of curvature i.e., + 20 cm.
What is the focal length of the concave mirror?
The distance between the pole of the concave mirror and the focus is known as the focal length of the concave mirror. The focal length of a concave mirror can be estimated by obtaining a real image of the distant object.
Which lens has a negative focal length?
Convex lens has negative focal length and concave lens has a positive focal length.
What is the focal length of a concave mirror and convex lens?
since the image formed by the mirror is real so that it can be obtained on the screen. 6. The distance between the pole O and principal focus F of a concave mirror is called the focal length of the mirror. It is equal to half the radius of curvature of the mirror.
How do you find the focal length of a convex lens?
The focal length of a convex lens is the distance between the center of the lens and the focal point. Here, F is the focal point and f is the focal length. Different lenses converge light at different focal points, and thus, have different focal lengths.
What is the definition of focal length in photography?
Define focal length. The distance between the convex lens or a concave mirror and the focal point of a lens or mirror is called the focal length. It is the point where parallel rays of light meet or converge. The focal length varies with the sign (positive or negative) depending upon the nature of the lens and mirror (concave or convex).
What is the principal focus of a convex lens?
Principal focus: Principal focus is defined as a point at which the reflected rays meet or appear to meet for the spherical mirror. For a concave mirror, the principal focus is in the front and for a convex mirror, the principal focus is at the behind. Below is an experiment to determine the focal length of a concave mirror and convex lens.
What is the difference between focal length and principal focus?
f is the focal length, which is the difference between the optical centre of the lens and the principal focus. The image can be obtained on the screen as the image formed by the lens is real. What is the focal length of a concave lens?