A burning candle whose flame is 1.5 cm tall is placed at a certain distance in front of a convex lens. An image of candle flame is received on a white screen kept behind the lens. The image of flame also measures 1.5 cm. If f is the focal length of convex lens, the candle is placed:(a) at f (b) between f and 2f (c) at 2f (d) beyond 2f

Tutorialspoint

Simply Easy Learning

---

Updated on 10-Oct-2022 10:50:58

0 Views

Print Article

• Related Articles
• A convex lens produces a magnification of + 5. The object is placed:(a) at focus (b) between $f$ and $2f$(c) at less than $f$ (d) beyond $2f$
• The image of a candle flame placed at a distance of 36 cm from a spherical lens is formed on a screen placed at a distance of 72 cm from the lens. Identify the type of lens and calculate its focal length. If the height of the flame is 2.5 cm, find the height of the image.
• To obtain a magnification of, –0.5 with a convex lens, the object should be placed:(a) at F (b) between optical centre and F(c) between F and 2F (d) beyond 2F
• A 1 cm high object is placed at a distance of 2f from a convex lens. What is the height of the image formed?
• In order to obtain a magnification of, $-$3 (minus 3) with a convex lens, the object should be placed:(a) between optical centre and F (b) between F and 2F(c) at 2F (d) beyond 2F
• An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens.
• When the object is placed between $f$ and 2$f$ of a convex lens, the image formed is(a) at $f$ (b) at 2$f$ (c) beyond 2$f$ (d) between O and $f$
• A virtual, erect and magnified image of an object is to be obtained with a convex lens. For this purpose,the object should be placed:(a) between 2F and infinity (b) between F and optical centre(c) between F and 2F (d) at F
• A student focuses the image of a candle flame, placed at about 2 m from a convex lens of focal length 10 cm, on a screen. After that he moves gradually the flame towards the lens and each time focuses its image on the screen.(A) In which direction does he move the lens to focus the flame on the screen?(B) What happens to the size of the image of the flame formed on the screen?(C) What difference is seen in the intensity (brightness) of the image of the flame on the screen?(D) What is seen on the screen when the flame is very close (at about 5 cm) to the lens?
• If a magnification of, –1 (minus 1) is obtained by using a converging lens, then the object has to be placed:(a) within $f$ (b) at $2f$(c) beyond $2f$ (d) at infinity
• An object is placed at a distance of 40 cm from a convex lens of focal length 30 cm. Find the position of the image.
• What is the position of image when an object is placed at a distance of 10 cm from a convex lens of focal length 10 cm?
• An object placed 4 cm in front of a converging lens produces a real image 12 cm from the lens.(a) What is the magnification of the image?(b) What is the focal length of the lens?(c) Draw a ray diagram to show the formation of image. Mark clearly F and 2F in the diagram.
• Describe with the help of a ray-diagram, the size, nature and position of the image formed by a convex lens when an object is placed beyond 2f in front of the lens.
• An object lies at a distance of $2f$ from a concave lens of focal length $f$. Draw a ray-diagram to illustrate the image formation.