Diverging Lens Identification: The Concave Lens
A diverging lens is an optical lens that spreads light rays apart. When parallel rays of light pass through a diverging lens, they are refracted in such a way that they seem to originate from a common point behind the lens. This behavior is characteristic of a specific type of lens.
Understanding Lens Types
Lenses are categorized based on how they refract light. The two primary categories are converging lenses (which bring light rays together) and diverging lenses (which spread light rays apart).
Characteristics of a Diverging Lens
- Spreads Light Rays: The defining feature is its ability to diverge, or spread out, parallel light rays.
- Shape: Typically, a diverging lens is thinner at the center and thicker at the edges.
- Focal Length: The focal length ($f$) of a diverging lens is considered negative ($f < 0$). The focal point is virtual, located where the refracted rays appear to diverge from.
Analyzing the Options
- Plano-Convex Lens: This lens has one flat surface and one convex (outwardly curved) surface. It acts as a converging lens.
- Convex Lens: This lens is curved outwards on both sides (or one side flat and the other convex). It converges parallel light rays to a focal point and is known as a converging lens. Its focal length is positive ($f > 0$).
- Cylindrical Lens: These lenses have a cylindrical shape and focus light onto a line rather than a point. They are used for specific applications like laser line generation, not primarily classified as simple diverging lenses.
- Concave Lens: This lens is curved inwards on both sides (or one side flat and the other concave). It is thinner at the center and thicker at the edges. When parallel light rays pass through it, they diverge. Therefore, the concave lens is known as a diverging lens.
Conclusion
Based on its optical properties of spreading parallel light rays, the concave lens is classified as a diverging lens.
Important Questions from Critical thinking (Notes)
- An empty plastic mug floats in a bucket of water. When a solid iron ball is kept in the mug it doesn't sink. When the ball is put in the water it sinks. Compared to when the ball is in water, the water level in the bucket when the ball is in the mug is
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Creative thinking always requires divergent thinking.
Reason (R): Divergent thinking helps in generating multiple solutions to a single problem.
In the light of the above statements, choose the most appropriate answer from the options given below:
- One day I lost my ear ring. To keep from losing earrings, further I used to thermocool to keep the earring in place. Using the thermocool as a temporary earring back showed that I overcome from the following:
- Match List - I with List - II.Choose the correct answer from the options given below :
List - I List - II A. Availability heuristic I. Presentation of information concening potential outcomes B. Representativeness heuristic II. Reference points that may lead us for problem solving C. Anchoring-and-Adjustment heuristic III. What comes to mind first D. Framing IV. Assuming that what is typical is also likely the solution - Select the correct statement related to learner centred approach
(a) Pupil is actively involved in the teaching-learning process.
(b) The main function of the teacher is not to instruct but to evoke learning.
Select the correct answer.
