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9th Science > Lights > Flashcards

Lights Flashcards

1
Q

Light is form of energy which a travel as

A

Electromagnetic waves

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2
Q

The branch of physics the deal with the properties and the applications of light is called

A

Optics

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3
Q

When the object is far away (at infinity)concave mirror
Image formed at?

A

Principal focus
Image is real , inverted and highly diminished in size

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4
Q

When the object is beyond the centre of curvature concave

A

Image formed between the principal focus service centre of curvature

Image is real inverter and smaller than object

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5
Q

And the object is at the centre of curvature concave

A

The image is at the centre of curvature itself
Image is real inverted and same size as the object

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6
Q

When the object is in between the centre of curvature and principle focus

A

The images beyond centre of curvature
Real inverted and magnified

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7
Q

When the object is at the principal focus concave

A

No image can be captured on the screen nor any virtual image can be seen

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8
Q

When the object is in between the focus and the pole

A

The image is behind the mirror
It is virtual erect and the magnified

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9
Q

We follow here set of sign convention called __________ to measure distance in ray diagram

A

Cartesian Sign convention

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10
Q

Cartesian sign convention is used to measure distance in_______

A

Ray diagram

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11
Q

Mirror equation

A

1/f = 1/u + 1/v
f focal length
U distance of the object
v distance of the image

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12
Q

Linear magnification m

A

m= hi/ho
Hi height of the image
Ho height of the object

m= -v/u

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13
Q

A negative sign in the value of magnification indicates that the images ______
A positive sign in the value of magnification indicates the image is ________

A

Real

virtual

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14
Q

Uses of concave mirror

A

Dentist head mirror
makeup mirror
torch
headlights
searchlight
solar heater

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15
Q

Stellar object are at an infinite distance. Therefore, image formed by a concave mirror would be the minister and inverted
Yet aasvanical telescope uses – mirror

A

Concave mirror

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16
Q

In early 17th century the Italian scientist who tried to measure the speed of light

A

Galileo Galilee

17
Q

In 1665 Danish astronomer who first estimated speed of light by observing one of the 12th moon of planet _______.

A

Ole Roemer
Jupiter

18
Q

Ole roemer estimated the speed of light to be about

A

220000 kilometre per second

19
Q

Some organisms can make their own light too this ability is called

A

Bioluminescence
Worms, fish, squid, starfish and some other organism that live in the dark sea habitat glow or flashlight to scare of predator

20
Q

In which year first language estimate was made by Armand fizeau

A

1849
today the speed of light in vacuum is known to be almost exactly 3 lakh kilometre per second

21
Q

The bending of light rays when the process obliquely from one medium to another medium is called

A

Refraction of light

22
Q

This deviation in the path of light is due to the change in velocity of light in the different medium

A

Velocity of light depends on the nature of medium in which travel. velocity of light is more in a rare medium(low optical density) than in a denser medium (high optical density)

23
Q

When ray of light travels from optical rare medium to optically denser medium it bends toward the?

When a Ray of light travel from an opticaly denser medium to an optically rare medium it Bends?

A Ray of light incident normally on a denser medium

A

1 Normal
2 It bends away from the normal
3 Goes without any deviation

24
Q

The law of refraction of light is also know as

A

Snell’s law of refraction

25
Q

_______ is the main cause for The spectacular brilliance of diamond and twinkling of stars

A

Total internal reflection

26
Q

The refractive index of the material of the core is ________ than that of the cladding

A

Higher

27
Q

Optical fibres work on the phenomenon of dash

A

Total internal reflection

28
Q

Who is the father of fibre optics

A

Narender Kapany

29
Q

_________is a form of energy which you produce the sensation of site

A

Light

30
Q

Distance between the pole and the principal focus of the spherical mirror is called

A

Focal length
F= R/2
R radius of curvature of mirror

31
Q

The angle of deviation depends on the refractive index of the glass

A

True

32
Q

The angle of deviation of light rays in a prism depend on the angle of

A

Incidence

33
Q

According to cartesian sign convention which mirror and which lens has negative focal length

A

Concave mirror and concave lens

34
Q

Find the size, nature and position of the image formed when an object of size 1 cm is placed at a distance of 15 cm from a concave mirror of focal length 10 cm.

A

-2 cm

Height of the image is -2 cm

35
Q

An object 2 cm high is placed at a distance of 16 cm from a concave mirror which produces a real image 3 cm high. Find the position of the image.

A

Position of image -24cm

9th Science (19 decks)

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