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Vaishnav K.v.
Subject: Science
, asked on 15/3/18
Q. A student places a candle flame at distance of about 60 cm from a convex lens of focal length 10 cm and focuses the image of the flame on a screen. After that he gradually moves The flame towards the lens and each time focuses the image on the screen.
(a) In which direction towards or away from the lens, does he move the screen to focus the image?
(b) How does the size of the image change?
(c) How does the intensity of the Image change as the moves towards the Lens?
(d) Approximately for what distance between the flame And the lens. the image formed or, the screen is inverted and of the same size?
Answer
1
Ananya Ashish Batra
Subject: Science
, asked on 15/3/18
To find the focal length of a concave mirror in an experiment, why should the distant object be sun rather than a distant tree?
Answer
1
Raghav Singh
Subject: Science
, asked on 15/3/18
Can i know how to take approx values correctly, many time we get an answer like 1.66 and write 1.67.... I usually dont like taking approx values because i fear it will be called wrong. I even fear what is the examiner seeing in the answer key , the approx value or the exact value. Please help me on this.
Answer
1
Raghav Singh
Subject: Science
, asked on 14/3/18
Will the refractive index table , which is there in NCERT come in the exams ?
Answer
1
Atharva Patil
Subject: Science
, asked on 14/3/18
why
u
is always negative in lens formula where u is equal to object which should be in plus
Answer
1
Champ Jee
Subject: Science
, asked on 14/3/18
What's the Color of two solutions. Q23.
23.
Aqueous solution of sodium sulphate and barium chloride filled in two test tubes A and B respectively. State the colour of two solutions. What is likely to happen if these solution are mixed together? Justify your answer.
Answer
3
Nazreen
Subject: Science
, asked on 14/3/18
What change do you expect in the focal length of a concave mirror and a convex lens when immersed in water. Justify your answer.
Answer
2
Harshita
Subject: Science
, asked on 14/3/18
Pls answer que 51 and 52
51. the focal length of the concave mirror in an experimental setup shown below, is
(a) 10.2cm
(b) 11.0​cm
(c) 11.4​cm
(d) 12.2cm
52. Four students, Ameeta, Zahira, Ravi and David performed the experiment of determination of focal length of a concave mirror separately. They measured the distance between the screen and the mirror as shown in the following diagram. Which one of there student is likely to get the correct value of local length of the convave mirror?
(a) Ameeta, (b) Zehira (c) Ravi (d) David.
Answer
2
Abhishek Gupta
Subject: Science
, asked on 14/3/18
14) With the help of a ray diagram explain the phenomenon of refraction of a ray through glass prism. Mark on the diagram - angle of prism, angle of incidence, angles of refraction, emergent ray and angle of deviation.
Answer
1
Manthra Bhaskar 💙🖤🖤ðŸ...
Subject: Science
, asked on 14/3/18
Solve this please...
Q. A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle, screen and the lens as under
Position of candle = 12.0 cm
Position of convex lens = 50.0 cm
Position of the screen = 88.0 cm
(i) What is the focal length of the convex lens?
(ii) Where will the image be formed if he shifts the candle towards the lens
Answer
3
Ankit Gangopadhyay
Subject: Science
, asked on 14/3/18
Answers?
Answer
4
Sahil Haque
Subject: Science
, asked on 13/3/18
Q 13. Draw ray diagram showing the image formation by a convex lens when an object is placed at twice the focal length of the lens.
Answer
1
Samyuktha M. S
Subject: Science
, asked on 13/3/18
answer 4th question
4.
Light is incident at an angle of
(i) 30
°
(ii) 45
°
, on the same face of a given rectangular slab. If the angles of refraction, at this face are r
1
and r
2
in the two cases. Obtain the relation in these angles?
Answer
1
Shreyas A K
Subject: Science
, asked on 13/3/18
If f
1
= the focal length of a concave lens ; f
2
= the focal length of a convex lens ; x = distance between the two lenses ; and F = total focal length (combined nature of the lenses) .Prove that 1/F = 1/f
1
+ 1/f
2
- x/(f
1
*f
2
)
Answer
1
Siddhi
Subject: Science
, asked on 13/3/18
If an optically denser medium need not have greater mass density then why speed is reduced in that medium?? What causes the speed to slow down?? Jaldi batao!!
Answer
3
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Q. A student places a candle flame at distance of about 60 cm from a convex lens of focal length 10 cm and focuses the image of the flame on a screen. After that he gradually moves The flame towards the lens and each time focuses the image on the screen.
(a) In which direction towards or away from the lens, does he move the screen to focus the image?
(b) How does the size of the image change?
(c) How does the intensity of the Image change as the moves towards the Lens?
(d) Approximately for what distance between the flame And the lens. the image formed or, the screen is inverted and of the same size?
23. Aqueous solution of sodium sulphate and barium chloride filled in two test tubes A and B respectively. State the colour of two solutions. What is likely to happen if these solution are mixed together? Justify your answer.
51. the focal length of the concave mirror in an experimental setup shown below, is
(a) 10.2cm
(b) 11.0​cm
(c) 11.4​cm
(d) 12.2cm
52. Four students, Ameeta, Zahira, Ravi and David performed the experiment of determination of focal length of a concave mirror separately. They measured the distance between the screen and the mirror as shown in the following diagram. Which one of there student is likely to get the correct value of local length of the convave mirror?
(a) Ameeta, (b) Zehira (c) Ravi (d) David.
Q. A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle, screen and the lens as under
Position of candle = 12.0 cm
Position of convex lens = 50.0 cm
Position of the screen = 88.0 cm
(i) What is the focal length of the convex lens?
(ii) Where will the image be formed if he shifts the candle towards the lens
4. Light is incident at an angle of
(i) 30
(ii) 45, on the same face of a given rectangular slab. If the angles of refraction, at this face are r1 and r2 in the two cases. Obtain the relation in these angles?