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# Monthly Archives: January 2013

## Why is it necessary to bend knees while jumping from a height?

Why is it necessary to bend knees while jumping from a height?

This is a consequence of the impulse momentum principle.

When we bent our knees on landing, the time of impact increases and reduces the average force exerted during the entire process. This prevents the chance of damage to our body.

Impulse momentum principle states that the impulse of a force is equal to the change in momentum produced.

Impulse is measured as the product of force and time interval. So, when we stop       ourselves, there is a fixed change in momentum. If we stop ourselves very fast, the time interval is less and the average force will be very large.

But, if we bent our knees during landing, the time involved in the proces of landing will be more and thus the average force will be less and hence the damage will also be less.

## Gauge Theory and Higgs Mechanism

What is Gauge Theory and how does it relate to electroweak symmetry? How does the breaking of a symmetry cause a reaction such as the obtaining of mass?

In particle physics, the Higgs mechanism is a kind of mass generation mechanism, a process that gives mass to elementary particles.

Gauge theory is the successful field theory explaining the dynamics of elementary particles.

## Ionizing Power of alpha and beta particles

Which has greater ionization power alpha or beta?

(Question received via speak pipe – a facility for the visitors to ask questions orally, if you have a mic)

Alpha particles have greater ionization power as they have two units of positive charge and 4 units of mass, whereas beta has only one unit of negative charge and negligible mass as compared to alpha.

## CBSE Class 10 Exam Date Sheet Announced

DATE-SHEET SECONDARY SCHOOL EXAMINATION,2013
DAY,DATE AND TIME SUBJECT NAME AND SUB-CODE

Friday,01st March, 2013 10:30 AM
PAINTING 049

Saturday,02nd March, 2013 10:30 AM
MATHEMATICS 041

Monday,04th March, 2013 10:30 AM
HINDI COURSE-A 002
HINDI COURSE-B 085

Tuesday,05th March, 2013 10:30 AM
MUSIC CAR.VOCAL 031
MUSIC CAR.INS.MEL. 032
MUSIC CAR.INS.PER. 033
MUSIC HIND.VOCAL 034
MUSIC HIND.INS.MEL 035
MUSIC HIND.INS.PER 036
ELEM BOOK-K & ACCY 254
E-TYPEWRITING-ENG 354
E-TYPEWRITING-HIN 454

Wednesday,06th March, 2013 10:30 AM
URDU COURSE-A 003
BENGALI 005
TELUGU 007
GUJARATI 010
MANIPURI 011
ASSAMESE 014
ARABIC 016
TIBETAN 017
FRENCH 018
GERMAN 020
PERSIAN 023
NEPALI 024
LIMBOO 025
LEPCHA 026
BODO 092
TANGKHUL 093
JAPANESE 094
BHUTIA 095
MIZO 098
BAHASA MELAYU 099
COMM. SANSKRIT 122
URDU COURSE-B 303Friday,08th March, 2013 10:30 AM
ENGLISH COMM. 101
ENGLISH LNG & LIT. 184

Saturday,09th March, 2013 10:30 AM
FOUNDATION OF I T 165

Monday,11th March, 2013 10:30 AM
PUNJABI 004
TAMIL 006
MARATHI 009
MALAYALAM 012
ODIA 013
SPANISH 096
KASHMIRI 097

Tuesday,12th March, 2013 10:30 AM
SOCIAL SCIENCE 087

Thursday,14th March, 2013 10:30 AM
SCIENCE-THEORY 086
SCIENCE W/O PRAC. 090

Friday,15th March, 2013 10:30 AM
HOME SCIENCE 064

Important – Regarding Class X School Based Assessment
Schools are being advised to conduct School Based Assessment
(Scheme 1) between 16th March to 31st March 2013.

## CBSE Exam 2013 Date Sheet Class 12

DATE-SHEET SENIOR SCHOOL EXAMINATION,2013

Friday,01st March, 2013 10:30 AM
ENGLISH ELECTIVE 001
FUNCTIONAL ENGLISH 101
ENGLISH CORE 301
Monday,04th March, 2013 10:30 AM
HISTORY 027
Tuesday,05th March, 2013 10:30 AM
PHYSICS 042
ELECTRIC MACHINES 623
FABRICATN.TECH-II 630
AC & REFRGTN-III 632
M PROD TPT &M COOP 640
OPTICS 658
CLINICAL BIO-CHEM. 661
COMM. HEALTH NURII 664
ACCOMODAT.SERVICES 691
CONFECTIONERY 698
CLSFN.&CATALOGUING 703
POULTRY PDTS& TECH 717
C HEALTH NURSING 731
Wednesday,06th March, 2013 10:30 AM
Friday,08th March, 2013 10:30 AM
POLITICAL SCIENCE 028
Monday,11th March, 2013 10:30 AM
CHEMISTRY 043
HERITAGE CRAFTS 070
OFF. COMMUNICATION 606
CONS BEHV & PROTCN 615
MGMT OF BANK OFFCE 621
APPLIED PHYSICS 625
FABRICATN.TECH-III 631
TV & VIDEO SYSTEMS 636
ELECTRICAL ENGG. 637
MILK & MILK PRODS. 639
BIOLOGY-OPTHALMIC 657
LAB. MEDICINE 660
FUND OF NURSING II 663
FOOD PREPARATIONII 690
INDIA-TOURIST DEST 693
FOOD SCI.& HYGIENE 696
PRIN &PRA-LIFE INS 705
POULTRY NUTR & PHY 716
INT TO FINANCL MKT 723
CRTV & COMM M M II 739
Wednesday,13th March, 2013 10:30 AM
GEOGRAPHY 029
LENDING OPERATIONS 620
AUTOSHOP REP& PRAC 628
I T SYSTEMS 699
Friday,15th March, 2013 10:30 AM
BIOLOGY 044
ACCOUNTANCY 055
SINDHI 108
PORTUGUESE 119
RUSSIAN 121
SPANISH 196
KASHMIRI 197
ELE.COST A/C & AUD 612
SALESMANSHIP 614
STORE ACCOUNTING 618
MECH. ENGINEERING 626
AUTO ENGINEERING 627
AC & REFRGTN-IV 633
YOGA ANATOMY &PHYS 656
MEAL PLNG & SERVIC 676
CLOTHING CONST 686
BASIC DESIGN 687
TOUR MGMT & MP PLN 695
REFERENCE SERVICE 704
Saturday,16th March, 2013 10:30 AM
HOME SCIENCE 064
Monday,18th March, 2013 10:30 AM
HINDI ELECTIVE 002
TAMIL 106
GUJARATI 110
MANIPURI 111
MALAYALAM 112
ODIA 113
ASSAMESE 114
TIBETAN 117
GERMAN 120
PERSIAN 123
NEPALI 124
LIMBOO 125
LEPCHA 126
BODO 192
TANGKHUL 193
JAPANESE 194
BHUTIA 195
BAHASA MELAYU 199
HINDI CORE 302
Wednesday,20th March, 2013 10:30 AM
MATHEMATICS 041
SECT PRAC & ACCNTG 605
CIVIL ENGINEERING 629
FLORICULTURE 643
COSMETIC CHEMISTRY 655
OPHTHALMIC TECH. 659
MICROBIOLOGY 662
MAT.&CHILD H.NURII 665
ESTB & MGMT OF FSU 677
TEXTILE SCIENCE 684
BAKERY SCIENCE 697
TPT. SYSTEMS &MGMT 712
POULTRY DISE & CNT 718
FIRST AID &MEDCL C 730
HEALTH CENTRE MGMT 733
FOOD PRODUCTIONIII 734
Friday,22nd March, 2013 10:30 AM
INFORMATICS PRAC. 065
COMPUTER SCIENCE 083
Saturday,23rd March, 2013 10:30 AM
FASHION STUDIES 053
SHORTHAND ENGLISH 608
SHORTHAND HINDI 610
ENGINEERING SCI. 622
ELN.DEV.& CIRCUITS 634
DAIRY PLANT INSTRU 641
VEGETABLE CULTURE 642
B THERAPY &H DR-II 654
DESG & PAT MAKING 685
DYEING & PRINTING 688
FOOD& BEV SERV. II 692
H EDN & PUB HEALTH 728
FOOD& BEV C & CNTL 737
Monday,25th March, 2013 10:30 AM
PHYSICAL EDUCATION 048
Saturday,30th March, 2013 10:30 AM
ECONOMICS 030
BIOTECHNOLOGY 045
ELECT APPLIANCES 624
Monday,01st April, 2013 10:30 AM
PAINTING 049
GRAPHICS 050
SCULPTURE 051
APP/COMMERCIAL ART 052
AGRICULTURE 068
CR WRTNG TR STUDY 069
Wednesday,03rd April, 2013 10:30 AM
SANSKRIT ELECTIVE 022
ENGG. GRAPHICS 046
BENGALI 105
TELUGU 107
MARATHI 109
ARABIC 116
FRENCH 118
MIZO 198
SANSKRIT CORE 322
MARKETING 613
EVOL& FORMS M M II 738
Thursday,04th April, 2013 10:30 AM
URDU ELECTIVE 003
DANCE-KATHAK 056
DANCE-BHARATNATYAM 057
DANCE-KUCHIPUDI 058
DANCE-ODISSI 059
DANCE-MANIPURI 060
DANCE-KATHAKALI 061
DANCE-MOHINIYATTAM 062
URDU CORE 303
Friday,05th April, 2013 10:30 AM
MUSIC CAR.VOCAL 031
MUSIC CAR.INS.MEL. 032
MUSIC CAR.INS.PER. 033
MUSIC HIND.VOCAL 034
MUSIC HIND.INS.MEL 035
MUSIC HIND.INS.PER 036
OFFCE PROC.& PRAC. 604
Saturday,06th April, 2013 10:30 AM
SOCIOLOGY 039
GRAPHIC DESIGNS 071
B P O SKILLS 724
Tuesday,09th April, 2013 10:30 AM
PSYCHOLOGY 037
FINANCIAL ACCNTG 611
Friday,12th April, 2013 10:30 AM
PHILOSOPHY 040
ENTREPRENEURSHIP 066
CASH MGMT & H-KEEP 619
POST HARV TECH&PRD 644
COMPUTER& LIFE I A 706
B CONCEPT-H &MED T 729
MIDWIFERY 732
FOOD PRODUCTION IV 735
FOOD SERVICES II 736
GEOSPATIAL TECH II 740
Tuesday,16th April, 2013 10:30AM
MULTIMEDIA & WEB T 067
MASS MEDIA STUDIES 072
TYPOGRAPHY &CA ENG 607
TYPOGRAPHY &CA HIN 609
Wednesday,17th April, 2013 10:30 AM
PUNJABI 104

## Plank’s Law and Compton Effect

I have a question,according to Planck’s law absorption or emission always happens as an integral multiple of hv(nu),bt in Compton effect an atom absorbs a fraction of energy of incident photon,can you explain?

Ananya Mukherjee
Mathew Abraham here absorbed and radiated or emitted photons are different. the scattered photons have greater wavelength and less frequency and energy.

In Compton effect the photon behaves like a particle which loses some energy due to inelastic collision.

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### CBSE Exam Count Down

AISSCE / AISSE 2020February 26, 2020
Board Exams for the core subjects of CBSE may start from 26 February (Class X) and 27 February (Class XII)