# power of lens formula class 10

## power of lens formula class 10

The S.I. 00:00. 00:00 . She has started this educational website with the mindset of spreading Free Education to everyone. Consider 2 lenses with focal length.When lens combine,they behave as a single lens of focal length. The power of a lens is specified as the inverse of the focal length in meters, or D =$\frac{1}{F}$, where D is the power in dioptres. ; The lens has a small aperture. Power of a lens is the ability to converge or diverge the ray of light falling on it. Last Updated on March 20, 2019 By Mrs Shilpi Nagpal Leave a Comment. Question 4 A convex and concave lens of focal length 50 cm and 40 cm are combined together,what is the power of the combination? 32. The focal length (f) of a converging lens is considered positive and that of a diverging lens is considered negative. It is denoted by the letter D. On this Page, we will Learn About the Following: The Focal Length of the Combined Lens is Given by. Numerical Methods In Lens (A) Lens Formula Definition: The equation relating the object distance (u), the image distance (v) and the focal length (f) of the lens is called the lens formula. Your email address will not be published. Hence, one dioptre is the power of a lens of focal length one meter. Q1: Which Lens has a More Power Thick or Thin? A lens of small focal length has large power of converging or diverging a parallel beam of light. Lenses, both converging and diverging, are the marvels of optical physics that use the ability of these media to refract, reflect, or bend light rays. This type of lens is called the equivalent lens for the combination. Fig.1 shows two lenses $L_{1}$ and $L_{2}$ placed in contact. Inclined Plane and Gear. When f = 1 meter, P = $\frac{1}{F}$ = 1/ 1 = 1 dioptre. Sign Convention. It is given as, \frac {1} {i} + \frac {1} {o} = \frac {1} {f} i= distance of the image from the lens. Doubt solving session of Electricity dated 1.5.20 practice numerical part 1. This is also known as diopter. Power of lens is 1 diopter if its focal length is 1 m. Consider 2 lenses with focal length.When lens combine,they behave as a single lens of focal length. Power of a lens. The original formula for lens power can be written substituting (u-1)/r1 for D1 and (u-1)/r2 for D2 to arrive at Dn = (u-1)/r1 + (u-1)/r2, aka the Lensmaker’s Equation. As the power of a lens is P =  1/F, eq (5) immediately gives. ; The lens has a small aperture. In general, the lenses come in two shapes: convex (curved outward) and concave (curved inward). Iit is defined as the ability of the lens to converge or diverge rays. The power of a lens is defined as the inverse of its focal length (f) in meters (m). Optical power (also referred to as dioptric power, refractive power, focusing power, or convergence power) is the degree to which a lens, mirror, or other optical system converges or diverges light.It is equal to the reciprocal of the focal length of the device: P = 1/f. Also, find the magnification produced by the lens. High optical power corresponds to short focal length. Author of this website, Mrs Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed (I. P. University) and has many years of experience in teaching. 00:00. If a Converging (Convex) Lens is Placed in Front of his Eyes, will he Feel that the Size has Increased? The thick convex lens has more power than a thin one because the thick one has a greater curvature and less focal length. Ans. Class 10 Physics Light Reflection Refraction. $\frac{1}{F}$ = (v - 1) ($\frac{1}{R_{1}}$ - $\frac{1}{R_{2}}$), P = (v - 1) ($\frac{1}{R_{1}}$ - $\frac{1}{R_{2}}$), Here, v = refractive index of the material, $R_{1}$ = Radius of curvature of the first surface of the lens, $R_{2}$ =  Radius of curvature of the second surface of the lens. Question 1 Find the power of concave lens of focal length 2m? i¹ + i² =A + δ. δ(min) = 2 i-A Chapter-5 Refraction through a lens. The power of a lens is specified as the inverse of the focal length in meters, or D =$\frac{1}{F}$, where D is the power in dioptres. The SI unit of power of a lens is ‘diopter’. : Power of lens, P= 1/f P= 1.5D f= 1/1.5 = 10… The power of a lens depends upon the curvature and focal length (f). 1 1 1 —- = —– + ——– Question 7 Give few applications of lens? Economics Chapter 1 Development – Notes & Study Material, Geography Chapter 6 Manufacturing Industries – Notes & Study Material. Thus, a lens having 1 metre of focal length has power equal to 1 dipotre. Doubt solving session of Electricity dated 22.4.20 from heating effect. Filed Under: Class 10, Light-Reflection and Refraction Tagged With: application of lens, diopter, power of lens. It is equal to P = $\frac{1}{F}$. 1         1         1. EFFECTIVE POWER FORMULA As long as thickness is not a factor, The Lensmaker’s Equation can be used effectively. Power of a lens. Question 2 Find the focal length of concave lens whose power is -2 D? ; The incident rays make small angles with the lens surface or the principal axis. Numerical Methods In Lens (A) Lens Formula Definition: The equation relating the object distance (u), the image distance (v) and the focal length (f) of the lens is called the lens formula. Also, the converging lens makes the images virtual and erect. This is true for any situation involving two thin lenses in contact. Filed Under: Class 10, Light-Reflection and Refraction Tagged With: application of lens, diopter, power of lens About Mrs Shilpi Nagpal Author of this website, Mrs Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed (I. P. University) and has many years of experience in teaching. ... Chapter-2 Work Power energy.