Lens

aLensLens is a piece of a refracting material bounded by at least a spherical surface. There are two types of lens i) Converging lensii) Diversing lens

Magnification (Linear)The linear magnification of a lens is defined as the ration of the soze of image produced by it to the size of the object . magnification (m) = size of image (I)

size of object (o) = image distance (V)

object distgance (u) Angular Magnification Visual angle: The angle subtended by the object at the eye is known as visual angle. The size of image formed by eye depends upon the visual angle. Greater the visual angle, greater is the image formed.

Angular MagnificationAngular Magnification is defined as the ratio of the angle subtended at the eye by the image formed by an optical instrument to that subtended at the eye by the object when not viewed through the instrument.angular magnification = visual angle with instrument (𝛽)

visual angle without lens (𝛼) Lens FormulaThe relation of focal length of a lens with the object distance and image distance is known as lens formula.1

f=1

u+1

vLens formula for a convex lens forming real image

Consider a convex lens of focal length f. let AB be an object placed normally on the principle axis of the lens figure. The ray of light from the object AB after refracting through the convex lens meets at point B’. so A’B’ is real image of the object AB.Since\(\Delta\) ‘s ABC and A’B’C’ are similar to their corresponding sides are proportional.

	∴AB A’B’	=CA CA’…(i)
	Similarly 𝛥‘sCDF and A’B’F are similar,
	∴CD A’B’	=CF FA’
	But CD=AB
	∴AB A’B’	=CF FA’…(ii)
	From equations (i) and (ii),we have
	CA CA’	=CF FA’
	or, CA CA’	=CF CA’-CF
	or, u v	=f v-f
	where, CA= u is object distance,
	CA'= v is image distance
	CF= f is focal length
	or, uv–uf	=vf
	or, uv	=uf+fv
	Dividing both sides by uvf
	uv uvf	=uf uvf+vf uvf
	1 f	=1 u+1 v which is lens formula.

Convex lens: when virtual image is formed.

Consider a convex lens of focal length f. Let AB be an object on the principle axis between the optical centre (C) and focus (F) of the lens. The rays of light from the object after refraction through the lens appear to come from point B’. So A’B’ is the virtual, erect and magnified image of the object in figure.Since\(\Delta\) ‘s ABC and A’B’C’ are similar to their corresponding sides are proportional

	∴AB A’B’	=CA CA’…(i)
	Similarly 𝛥‘sCDF and A’B’F are similar,
	∴CD A’B’	=CF A’F
	But CD=AB
	∴AB A’B’	=CF A’F…(ii)
	From equations (i) and (ii),we have
	CA CA’	=CF A’F
	or, CA CA’	=CF CA’+CF
	or, u -v	=f -v+f
	where, CA= u is object distance,
	CA’=- v is image distance
	CF= f is focal length
	or, -uv+uf	=-vf
	or, uv	=uf+vf
	Dividing both sides by uv
	1	=f v+f u
	1 f	=1 u+ 1 v which is lens formula.

Lens formula in concave lens

Consider a concave lens of focal length f. Let AB be an object placed normally on the principle axis of the lens. A’B’ is the virtual image of the object AB formed by concave lens.Since\(\Delta\) ‘s ABC and A’B’C’ are similar to their corresponding sides are proportional

	∴AB A’B’	=CA CA’…(i)
	Similarly 𝛥‘sCDF and A’B’F are similar,
	∴CD A’B’	=CF A’F
	But CD=AB
	∴ AB A’B’	=CF A’F…(ii)
	From equations (i) and (ii),we have
	CA CA’	=CF A’F
	or, CA CA’	=CF CF-CA’
	or, u -v	=-f -f+v
	where, CA= u is object distance,
	CA’=- v is image distance
	CF=- f is focal length
	or, uv-uf	=vf
	or, uv	=uf+vf
	Dividing both sides by uv
	1	=f v+f u
	1 f	=1 u+1 v which is lens formula.

Lens maker FormulaThe relation of focal length of a lens with the refractive index of the material it is made with and the radii of curvatures is known as lens maker formula.1

f=(𝜇-1) (1

R1 +1

R2)Proof:

Consider a thin convex lens of focal length f and refractive index µ. Suppose a ray OP parallel to the principle axis incident on the lens at a small height, h above it. After refraction, the ray will pass through the focus F as shown in the figure and deviates through an angled. The angle of deviation is given by

	tan𝛿	=h f
	Since𝛿 is small,tan𝛿=𝛿,and
	𝛿	=h f…(i)

The portion PQ of the lens is a small angle prism which is formed by two tangent planes to the lens surfaces at P and Q. Since the angle of deviation in small angle prism is independent of the angle of incident, equation (i) is equal to the angle of deviation in such prism,

	𝛿=A(𝜇-1)𝛿…(ii)
	where A is the small angle of the prism.
	From equation (ii)and (iii),we have
	h f	=A(𝜇-1 )
	or, 1 f	=A h(𝜇-1)…(iii)

Let C1 and C2 be the centre of curvature of the two spherical surfaces. In figure PC1 = R1 is normal at P and OC2 = R2 normal at Q where C1 and C2 are centre of curvature of lens surfaces. Let ϴ and Ф be the angles made by R1 and R2 with the principal axis. Since the angle between two tangents forming a prism is equal to the angle between two radii, so we have

	∠PKC=∠QKC1=A
	From the geometry, we have
	A	=𝜃+𝜙
	and for small angles,𝜃=h R2 and 𝜙=h R1,and then
	A	=h R2+h R1
	or, A h	=1 R1+1 R2…(iv)
	Substituting equation (iv)in equation (II), we get
	1 f	=A h(𝜇-1)
	or, 1 f	=(1 R1+1 R2)(𝜇–1)
	or, 1 f	=(𝜇–1)(1 R1+1 R2)…(v)

This is lens maker’s formula. Here µ is refractive index of lens material to the medium outside.Combination of thin lenses in contactLet us consider two lenses A and B of focal length f1 and f2 placed in contact with each other. An object is placed at O beyond the focus of the first lens A on the common principal axis. The lens A produces an image at I1 . This image I1 acts as the object for the second lens B. The final image is produced at I as shown in Fig. Since the lenses are thin, a common optical centre P is chosen.

Let PO = u, object distance for the first lens (A), PI = v, final image distance and PI1 = v1, image distance for the first lens (A) and also object distance for second lens (B). For the image I1 produced by the first lens A, 1

f1=1

u+1

v1.............(i) For the final image I, produced by the second lens B, 1

f2=1

-v1+1

v............. (ii) Adding equations (i) and (ii), 1

f1+1

f2=1

u+1

v1-1

v1+1

v1

f1+1

f2=1

u+1

v.................(iii) If we consider the cobination of lens as a single lens, u is object distance and v is final image distance. If F is focal length of the combination, then. 1

F= 1

u+1

v..............(iv) From equations (iii) and (iv) 1

F= 1

f1+1

f2 This F is the focal length of the equivalent lens for the combination. The derivation can be extended for several thin lenses of focal lengths f1, f2, f3 ... in contact. The effective focal length of the combination is given by 1

F=1

f1+1

f2+1

f3+............. so, the power of the combination will be P = P1 + P2 + P3 + .... i.eThe power of a combination of lenses in contact is the algebraic sum of the powers of individual lenses.The combination of lenses is generally used in the design of objectives of microscopes, cameras, telescopes and other optical instruments.Power of lensPower of lens is a measure of its abilitu to converse of diverse the ray of light. It is defined as the reciporcal of the focal length.power(P) = 1

f Its unit is Diopter (D).For a combination of lenses combined power is given byP = 1

f1+1

f2+1

f3+.............=P1+P2+P3+..........

Capacitor

Electric Potential

 Electric Potential

HPE

 SET I

Subject: Health, Population and Environment               Time: 2:15 hrs.

Candidates are required to give their answers according to the given instruction.

 

Attempt all the questions:

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Group 'A'

 

Very short answer questions.                        11×1=11

clt 5f]6f] pQ/ cfpFg] k|Zgx¿ .

1. What is meant by Psychological aspect?dgf]j}1flgs kIf eg]sf] s] xf] <

2. How is RNI computed?RNI s;/L lgsflnG5 <

3.  When was Brundland Commission formed?a|'G8Nof08 sld;g slxn]

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4. In whichgeographical belt is Ruru Kshetra located?g]kfnsf]

s'g ef}uf]lns If]qdf ¿¿ If]q kb{5 <

5. What is the score of Nepal according to Human Development Index 2015 A.D.?;=g\= @)!% sf] dfgjljsf; ;"rs cg';f/ g]kfnsf] :sf]/ slt 5 .

6. How many types of medicinal plants are found in Nepal?

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7. Mention the causative agent of amoebic dysentery?

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8. What is hypertension?  xfOk/6]g;g eg]s s] xf] <

9. Write the full form of 'GENETUP'.'GENETUP' sf] k'/f¿k n]Vg'xf];\ .

10. What do you mean by safety life style?;'/lIft hLjg z}nL eGgfn] s]

a'lemG5 <

11. Write one symptom of Choking?rf]lsªsf] Pp6f nIf0f n]Vg'xf];\ .

Group 'B'

Short answer questions:                                9×4=36

5f]6f] pQ/ cfpFg] k|Zgx¿ .

12. Show the inter-relationship among health, population and environment from political and biological aspects.

:jf:Yo hg;+Vof tyf jftfj/0fsf] cGt/;DaGw /fhg}lts / h}ljs kIfaf6 b]vfpg'xf];\ .

13. In a certain city of Nepal has 45,000 people on the day of a year and 55,000 at the last day of the year. 1500 were the people who came from another country and 500 left the country. 1500 were born and 500 died.Now find out PGR.g]kfnsf] s'g} Ps zx/df jif{sf] klxnf] lbgdf $%,))) hg;+Vof lyof] / o;sf] cGTodf %%,))) eof] . p;}jif{ !%)) hgf csf]{ b]zaf6 cfP / %)) hgfn] pQm b]z 5f]8] .!%)) hgf hlGdP / %)) hgf d/] . pQm zx/sf] hg;+Vof j[l4b/ lgsfNg'xf];\ .

or -cyjf_

Show the effects of rapid population growth on the health and cultural heritage.hg;+Vof j[l4b/n] :jf:Yo / ;f+:s[lts ;Dkbfdf s:tf] c;/x¿ b]lvG5g\ <

14. Explain the objectives of sustainable development.

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15. Compare the Socio-cultural aspects of Himalayan and Hilly Regions.lxdfnL / kxf8L k|b]zsf ;f+:s[lts kIfx¿ aLr t'ngf ug'{xf];\ .

16. Differentiate between HDI and PQLI.HDI / PQLI aLr km/s

5'6\ofpg'xf];\ .

17. What are the challenges for bio-diversity conservation?

     h}ljs ljljwtf ;+/If0fsf r'gf}ltx¿ s] s] x'g\ <

or -cyjf_

Write short notes on(5f]6f] l6Kk0fL n]Vg{'xf];\ ._

a) Clouded Leopard-Wjf;] lrt'jf_

b) Asaitic Rock Python -Pl;l6s /s kfOhf]g_

18. What are causes and symptoms of Cancer? Explain in short.SofG;/ /f]usf sf/0f / nIf0fx¿nfO{ JofVof ug'{xf];\ .

19. What suggestions do you give to make your friend free from Drug Addiction?8«u Pl8S;gaf6 ;'/lIft x'g ltdL ltd|f] ;fyLnfO{ s] ;'emfax¿ lbG5f}F <

20. Why is community health important?;fd'bflos :jf:Yo lsg dxTjk"0f{ 5 <

or -cyjf_

What first aid do you provide for the victim of high altitude sickness.n]s nfu]sf] lj/fdLnfO{ ltdL s] s:tf] k|fylds pkrf/ u5f}{ <

Group 'C'

Long answer questions.                                           4×7=28

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21. The population growth rate of Nepal by 2001 and 2011 is 2.25 and 1.35 percent respectively? Analyze them with major causes behind the situation.g]kfndf hg;+Vof j[l4b/ @=@% / !=#% k|ltzt qmdz ;=g\=@))! / @)!! df x'g\ uof] . of] o:tf] cj:yf x'gsf k5fl8 s] s] sf/0fx¿ x'g ;S5g\ ljZn]if0f ug'{xf];\ .

22. "Change in consumption pattern of resources is the best policy to conserve biodiversity." Elaborate it.æh}ljs ljljwtf ;+/If0fsf] pQd pkfo k|fs[lts ;|f]tx¿sf] pkof]lutfdf kl/jt{g Nofpg' g} xf] .Æ JofVof ug'{xf];\ .

23. How can we increase the level of quality of life of society? Write down.xfdLn] xfd|f] ;dfhsf] u'0f:t/Lo hLjg s;/L j[l4 ug{ ;S5f}F <n]Vg'xf];\ .

24. The most appropriate health services are preventive health services in Nepal. How can we make them effective?       g]kfndf ;a}eGbf pko'Qm :jf:Yo ;]jfx¿ lg/f]wfTds :jf:Yo ;]jfx¿ x'g\ < o;nfO{ k|efjsf/L agfpg xfdL s] ug{ ;S5f}F <

ÂÂ

SET II

Class : X                       F.M 75            Time 2:15 Hrs

Candidates are required to write their answers according to the instructions given.

 

Attempt all questions.

 

Group 'A'

 

Give very short answers.                                          (11´1=11)

1. Under which aspect of environment does non-living things fall?

2. How is PGR calculated?

3. Mention the areas of application of sustainable development.

4. Write any two importance of development.

5. What is the range of HDI?

6. Which part of himalayan yew has the medicinal value?

7. Mention any two non modifiable risk factors.

8. What is the objective of MCHC?

9. Write two elements of curative health service?

10. What do you mean by burn?

11. Write the application of artificial respiration.

 

Group 'B'

 

Short answer questions:                                           [9×4=36]

12. What is the scope of population education?

13.       Midyear population of certain village of Kailali was 975 in 2011. If 34 people from that village went to India, 26 people came to that village to settle permanently, calculate in-migration rate and net migration rate.

OR

      Discuss various measures of death rate.

14.       Write about the principles of sustainable development. Explain any four.

15.       What sorts of adverse impacts are seen in biological aspects of terai region?

16.  Enlist the efforts that you would make to attain the quality of life?

17. Discuss about the need of conserving biodiversity?

OR

      Prepare a leaflet about spike nard.

18.       What is rheumatic heart disease? How can you know a person is suffering from it?

19. What are the conditions of risk pregnancy?  

20. Differentiate between preventive and curative health services.

OR

      Write in short about the first aid care needed in electric shock.

 

Group'C'

 

Long answer question.                                              [4×7=28]

21.       Discuss the interrelationship among health, population and environment under various aspects.

22. What are the importance of quality life?

23.       Why are the young people more vulnerable to STDs in Nepal? Mention the measures that can be followed to control such disease.

24.       What is safe motherhood? Present the immunization chart   that should be followed to the infants. 

 

hög

SET III

Subject: HPE                                                  Time: 2 hours 15 minutes

 

Students are required to give their answers in their own words as far as possible.

All Questions are compulsory

Group ‘A’ [11×1=11]

Very Short Answer Question:

1.  What is environment education?

2.  Write down the formula to calculate age specific fertility rate

3.  Write a reason for not having balanced regional development in Nepal.

4.  How much percentage of people live in Terai region according to census 2011A.D.?

5.  How does saving help a family to obtain quality life?

6.  Write the name of plant which is used to cure cancer.

7.  What is the causative agent of dengue fever?

8.  Write the full form of COPD.

9.  What is sexually transmitted disease?

10.In which service patients get treatment without admitting in hospital?

11.Which part of body is affected by electric shocks?

Group B [9x4=36]

Short Answer Question: 

12. Write any two aspects under health population and environment? Describe them briefly.

13. Describe any four consequences of rapid population growth on environment.

Or

    There were 1120 people of the age group between 0-14yrs, 600 of the age group of 60 years and above, 2505 of the age group 15-59 years out of 4,225 in any district in 2074 B.S If the number of males were 2120 find the dependency ratio and sex ratio.

14. Why is people participation needed for sustainable development? Mention in any four points.

15. What is meant by ecosystem? Write any three effects on ecosystem of Terai region.

16. How does marriage and first conception of child at appropriate age helps to obtain quality of life. Describe.

17. Mention the role of biodiversity in tourism development of Nepal in any four points.

Or

     Mention any four roles of local people to conserve the endangered animals.

18. Write any four measures to save from anemia.

19. Define safe motherhood. Explain the services included by safe motherhood.

20. Frist aid prevents the condition of injured individual from spoil. Give reasons.

Or

     Why is unhealthy lifestyle responsible for different health problems? Justify with suitable examples.

Group C(4x7=28)

Long Answer Question:

21.Describe any seven principles of sustainable development in       brief.

22. What measures do you take in the management and conservation of environment? State any seven measures.

23. Write any four symptoms of cancer and three preventive measures of it.

24.Most of the people in your community take alcohol as the ritual. To change that ritual what strategies do you apply? Explain.

 

 

***