Friday, 23 September 2022

What is mirror, types of mirror and mirror formula class 10th science numerical

What is mirror?

A mirror is a reflective surface that bounces off light, producing either a real image or a virtual image.

Types of mirror

 Mirrors are mainly three types are plane mirrors and concave and convex mirrors.

Concave mirror :-  If the inner side of the spherical mirror is reflecting, it is called a concave mirror. 


Convex Mirror : If the outer side of the spherical mirror is reflecting, it is called a convex mirror.

Characteristics of the image formed by a plane mirror. 

(i) The Image is erect. 

(ii) The Image is of the same size as that of the object. 

(iii) The image is laterally inverted. Right side appears to be left and left side appeared to be right. 

(iv) The image is virtual.







Thursday, 22 September 2022

Reflection and refraction of light lens formula Class 10th science Numerical

Lens :- A transparent material bound by two surfaces, of which one or both surfaces are spherical is called the lens.

There are two types of lenses:

i. Convex (Converging) lens- Convex lenses are thick in the middle and thinner at the edges. A convex lens is also known as the converging lens because it converges parallel light rays inwards to a point known as the focal point.

ii. Concave (Diverging) lens- Concave lenses are flat in the middle and thicker at the edges. The concave lens is also known as a diverging lens because it diverges the parallel light rays outward from a point knows as the focal point.

Lens formula:

If u = object distance, v = image distance and

f = focal length of lens,then the lens formula is given by

According to sign conventions we need to assume the distance as follows,

Object distance, u= -ve , Image distance, v = -ve/+ve (depends upon the position of image) and Focal length, f= -ve for concave lens/+ve for convex lens.

 

Let’s consider following example to understand this formula more precisely.

Ex.1) An object is kept in front of converging lens of focal length 20 cm at distance of 10 cm. Find position of image, nature of image.

Solution: Data given ;( using all sign conventions)

Focal length, f= +20 cm

Object distance, u= -10 cm

Image distance=?

Formula:

On substituting the above values, we get

∴ 1/v = 3/20

∴ v = 20/3

∴ v = 6.67 cm

Positive value of ‘v’ indicates that image is real but inverted.

Magnification by lenses (M):

Magnification is defined as the ratio of height of image (h2) to the height of object (h1) or the ratio of image distance (v) to object distance (u).

Ex.2) An object of height 5 cm kept in front of convex lens of focal length 25 cm at distance of 10 cm. Find position of image, nature of image and height of the image.

Solution: Data given ;( using all sign conventions)

Height of object, h1= + 5 cm

Focal length, f= +25 cm

Object distance, u= -10 cm

Image distance=?

Image height=?

Formula:

∴ 1/v = 35/200

v = 200/35

∴ v = 5.7 cm

Positive value of ‘v’ indicates that image is real but inverted.

Now to calculate height of image use 2nd formula

Hence the height of image obtain here will be 2.85 cm.

(3) The distance of object is 20cm from convex mirror of focal length is 25 cm. Find the position of image?

Given:

F = 15 => convex mirror

Object distance u = -20 cm

Image distance (v) =?

1/f = 1/v + 1/u

1/25 = 1/v + 1/-20

1/25 + 1/20 = 1/v

45/500 = 1/v

V = 500/45 = 11.11

V = 11.1100

The value of  V is +ve so image is virtual.

(4) The radius of curvature is 38 cm. Find the focal length of convex mirror?

Given:

R = 38 cm

Focal length is equal to half of radius of curvature

Focal length = R/2

= 28/2

F = 19 cm

Focal length is 19 cm

(5) Find the position of image if the focal length of convex lens (f) is 8 cm and object is placed 16 cm from lens.

Given:

f = 8 cm

u = – 16 cm

v =?

1/f = 1/v – 1/u

1/8 = 1/v – 1/16

1/v = 1/8 – 1/16

1/v = 1/16

V = 16 cm

∴ The image is placed 16 cm from the principal axis.

Chemical Names and Common Name of Chemical Formula in Hindi

 Chemical Names and Common Name of Chemical Formula
रासायनिक सूत्रो के रासायनिक नाम व सामान्य नाम

सामान्‍य नाम

रासायनिक यौगिक

रासायनिक सूत्र

ब्लीचिंग पाउडर

कैल्शियम ऑक्‍सीक्‍लोराइड

CaOCL2

चाक (संगमरमर)

कैल्शियम कार्बोनेट

CaCo3

बेकिंग पाउडर

सोडियम बाइकार्बोनेट

NaHCO3

पोटाश एलम

पोटेशियम एल्युमिनियम सल्फेट

KAl(SO)·12HO

नीला थोथा

कॉपर सल्फेट

CuSO4.xH2O

बुझा चूना

कैल्शियम हाइड्रॉक्साइड

Ca(OH)2

त्वरित चूने

कैल्शियम ऑक्साइड

CaO

क्लोरोफॉर्म

ट्राइक्‍लोरो मीथेन

CHCl3

कास्टिक सोडा

सोडियम हाइड्रॉक्‍साइड

NaOH

कास्टिक पोटाश

पोटेशियम हाइड्रॉक्‍साइड

KOH

शुष्‍क बर्फ

ठोस कार्बन डाइ आक्‍साइड

CO2

सिरका

एसिटिक एसिड

CH3COOH

धावन सोडा

सोडियम कार्बोनेट

Na2CO3

प्लास्टर ऑफ पेरिस

कैल्शियम सल्फेट

CaSO4. 1/2 H2O

एप्‍सम

मैग्नीशियम सल्फेट

MgSo4

जिप्सम

कैल्शियम सल्फेट

CaSo4. 2H2O

भारी जल

ड्यूटेरियम ऑक्साइड

D2O

हरा थोथा

फेरस सल्फेट

FeSo4

मोहर लवण

अमोनियम फेरस सल्फेट

(NH4)2Fe(SO4)2·6H2O

सफेद थोथा

जिंक सल्फेट

ZnSo4.7H2O

मार्श गैस

मीथेन

CH4

रेत

सिलिकॉन ऑक्साइड

SiO2

मैग्नीशिया

मैग्नीशियम ऑक्साइड

MgO

हँसाने वाली गैस

नाइट्रस ऑक्साइड

N2O

वरमेलियम

मरक्‍यूरिक सल्फाइड

HgS

चीनी

सुक्रोज

C12H22O11

T.N.T.

ट्राइनाइट्रो टाइलून

C7H5N3O6

Wednesday, 21 September 2022

भारत में शास्त्रीय भाषाओं को शास्त्रीय भाषा का दर्जा प्रदान किया गया

भारत में शास्त्रीय भाषाएँ



वर्तमान में छ: भाषाओं को वर्ष 2004- 2014 तक शास्त्रीय भाषा का दर्जा प्रदान किया गया जो इस प्रकार हैं-

  • तमिल (2004)
  • संस्कृत (2005)
  • कन्नड़ (2008)
  • तेलुगू (2008)
  • मलयालम (2013)
  • ओडिया (2014)

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