Concave Lens Ray Behavior Analysis
Understanding Refraction in Concave Lenses
A concave lens is a diverging lens. It spreads out light rays that pass through it.
According to the rules of ray optics for a concave lens:
- Any light ray travelling parallel to the principal axis, after passing through the concave lens, bends outwards (diverges).
- This diverging ray, when traced backward, appears to originate from a specific point on the principal axis.
- This point is the first principal focus (F1) of the concave lens, located on the same side as the incident ray.
Evaluating the Options
Based on the rules:
- Option 1 is incorrect because passing through the second principal focus is characteristic of parallel rays refracted by a convex lens.
- Option 2 correctly states that the ray appears to diverge from the first principal focus. This is the defining behavior for a ray parallel to the principal axis in a concave lens.
- Option 3 is incorrect. Rays emerge parallel only if they pass through the optical center.
- Option 4 is incorrect. The ray does not pass through 2F, and 2F is not solely defined as the radius of curvature in this context.
Therefore, the correct description of the light ray's path after refraction is that it appears to diverge from the first principal focus.
Similar Questions
A ray of monochromatic light is passing through an equilateral prism (ABC) as shown in the figure. The refracted ray (QR) is parallel to the base (BC) and the angle of incidence ($i$) is $50^\circ$. Then the angle of deviation ($\delta$) is :
- In interference and diffraction, the light energy is redistributed. If it reduces in one region, producing a dark fringe, it increases in another region, producing a bright fringe.
A. As there is no gain or loss of energy, these phenomena are consistent with the principle of conservation of energy.
B. Diffraction and interference are characteristics exhibited only by light waves.
Choose the correct answer from the options given below : - In Young's double slit experiment, using monochromatic light of wavelength $\lambda$, the intensity of light at a point on the screen where the path difference is $\lambda$, is $K$ units. The intensity of light at a point where the path difference is $\lambda/3$ will be :
Consider three media P, Q and R with refractive indices $1$, $1.25$, and $1.5$, respectively. The medium Q having a thickness of $5\text{ cm}$ is placed between extended media P and R as shown in the figure. An object O is placed at the center of medium Q. If viewed from medium P near the normal direction, the apparent depth of O is $h_1$. For similar observation from medium R, the apparent depth is $h_2$. The value of $|h_1 - h_2|$, in cm, is :
The lens combination as shown in the figure, consists of two lenses, $L_1$ and $L_2$, of the focal lengths $+10\text{ cm}$ and $-10\text{ cm}$, respectively. The position of the image formed is :
Important Questions from Optics
- A point source is kept at the center of a spherically enclosed detector. If the volume of the detector increased by 8 times, the intensity will
- Five persons $\text{P}_1, \text{P}_2, \text{P}_3, \text{P}_4 \text{ and } \text{P}_5$ recorded object distance ($u$) and image distance ($v$) using same convex lens having power $+5\text{D}$ as $(25, 96), (30, 62), (35, 37), (45, 35)$ and $(50, 32)$ respectively. Identify correct statement
- In the Young's double slit experiment the intensity produced by each one of the individual slits is $I_o$. The distance between two slits is $2 \text{ mm}$. The distance of screen from slits is $10 \text{ m}$. The wavelength of light is $6000 \text{ \AA}$. The intensity of light on the screen in front of one of the slits is _______.
- In a microscope the objective is having focal length $f_o = 2 \text{ cm}$ and eye-piece is having focal length $f_e = 4 \text{ cm}$. The tube length is $32 \text{ cm}$. The magnification produced by this microscope for normal adjustment is ____________.
- A collimated beam of light of diameter $2 \text{ mm}$ is propagating along x-axis. The beam is required to be expanded in a collimated beam of diameter $14 \text{ mm}$ using a system of two convex lenses. If first lens has focal length $40 \text{ mm}$, then the focal length of second lens is ____________ $\text{mm}$.
