Doubtly
@Doubtly · Joined Feb 2021
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- Where should an object be placed in front of a convex lens to get a real image of the size of the object? b) At twice the focal length 2
- The image formed by a concave mirror is observed to be virtual, erect and larger than the object. d) Between the pole of the mirror and its principal focus. 2
- Which one of the following materials cannot be used to make a lens? (a) Water (b) Glass (c) Plastic (d) Clay Correct option is d) Clay 2
- Find the power of a concave lens of focal length 2 m. Focal length of concave lens, f = 2 mPower of lens, P= 1/f = 1/(-2)= -0.5D 1
- A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it Since the image is real and same size. The position of image should be at 2F. It is given that the image of the needle is formed at a distan... 1
- Define 1 dioptre of power of a lens. The SI unit of power of lens is dioptre which is denoted by the letter D. 1 dioptre is defined as the power of a lens of focal length 1 metr... 1
- The refractive index of diamond is 2.42. What is the meaning of this statement? The refractive index of diamond is 2.42. This means that the speed of light in diamond will reduce by a factor of 2.42 as compared to its sp... 1
- You are given kerosene, turpentine and water. In which of these does the light travel fastest? In water light travel faster as compare to kerosene and turpentine because the refractive index of water is lower than that of kerosene and... 1
- Find out, from Table, the medium having highest optical density. Also find the medium with lowest optical density. Highest optical density = Diamond Lowest optical density = Air Optical density of a medium is directly related with the refractive index of... 1
- Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? Refractive index of a medium, n_m = Speed of light in vacuum/Speed of light in the medium Speed of light in vacuum, c = 3 × 10⁸ ms⁻¹ Refract... 1
- A ray of light travelling in air enters obliquely into water. Does the light ray bend towards the normal The ray of light bends towards the normal. When a ray of light enters from an optically rarer medium (having low refractive index) to an opt... 1
- A concave mirror produces three times magnified (enlarged) real image of object placed at 10 cm in front of it. The magnification(m) is given as = -3 (as image is real) object distance(u) = -10 cm image distance (v)=? we know that m= -v/u -3 = -v /-10... 1
- Find the focal length of a convex mirror whose radius of curvature is 32 cm. Radius of curvature, R= 32 cm Radius of curvature = 2 × Focal length (f) R= 2ff= R/2 = 32/2 = 16 Hence, the focal length of the given convex... 1
- Why do we prefer a convex mirror as a rear-view mirror in vehicles? We prefer a convex mirror as a rear-view mirror in vehicles because it gives a wider field of view, which allows the driver to see most of t... 1
- Name the mirror that can give an erect and enlarged image of an object. Concave Mirror 2
- The radius of curvature of a spherical mirror is 20 cm. What is its focal length? Radius of curvature, R= 20 cm Radius of curvature of a spherical mirror = 2 × Focal length (f)R= 2f f= R/2 = 20 / 2 = 10 Hence, the focal le... 1
- Define the principal focus of a concave mirror. Light rays that are parallel to the principal axis of a concave mirror converge at a specific point on its principal axis after reflecting f... 1
- Only variations that confer an advantage to an individual organism will survive in a population. We agree with the statement that Only variations that confer an advantage to an individual organism will survive in a population. All the va... 2