NCERT Solutions
Board Paper Solutions
Ask & Answer
School Talk
Login
GET APP
Login
Create Account
Popular
Latest
Expert Answers
ALL
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
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) 11.0â€‹cm
(c) 11.4â€‹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’™ðŸ–¤ðŸ–¤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
$\xb0$
(ii) 45
$\xb0$
, 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
Jeevaj
Subject: Science
, asked on 13/3/18
Other than plane mirrors what other types of mirrors and lenses provide lateral inversion
Answer
3
Champ Jee
Subject: Science
, asked on 13/3/18
Sample Problem 3.
The rear view mirror of a car is plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear view mirror, the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be:
(a) 1 m/s
(b) 2 m/s
(c) 4 m/s
(d) 8 m/s
Answer
3
Payal Arora
Subject: Science
, asked on 13/3/18
Q). Draw a diagram to trace the path of a ray light incident at angle of 40
$\xb0$
on a rectangular glass slab. Write the measure of the angle of refraction and angle of emergence.
Answer
2
Payal Arora
Subject: Science
, asked on 12/3/18
A student focuses the image of a candle name, placed at about 2 from a convex lens of focal length 10 cm, on a screen. After that he gradually moves 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?
Answer
2
Prev
3
4
5
6
7
Next
What are you looking for?

whyuis always negative in lens formula where u is equal to object which should be in plus51. the focal length of the concave mirror in an experimental setup shown below, is

(a) 10.2cm

(b) 11.0â€‹cm

(c) 11.4â€‹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$\xb0$

(ii) 45$\xb0$, 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?_{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})Sample Problem 3.The rear view mirror of a car is plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear view mirror, the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be:(a) 1 m/s

(b) 2 m/s

(c) 4 m/s

(d) 8 m/s

(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?