CBSE Board Paper 2022 (Marking Scheme and Solutions) | Physics Class 12 - NEET PDF Download

 Page 1


042_55/1/1_Physics # Page-1 
  
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – PHYSICS (SUBJECT CODE – 042) 
(PAPER CODE – 55/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct assessment 
of the candidates. A small mistake in evaluation may lead to serious problems which may affect the 
future of the candidates, education system and teaching profession. To avoid mistakes, it is 
requested that before starting evaluation, you must read and understand the spot evaluation 
guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to public in 
any manner could lead to derailment of the examination system and affect the life and future 
of millions of candidates. Sharing this policy/document to anyone, publishing in any 
magazine and printing in News Paper/Website etc may invite action under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be done 
according to one’s own interpretation or any other consideration. Marking Scheme should be strictly 
adhered to and religiously followed. However, while evaluating, answers which are based on 
latest information or knowledge and/or are innovative, they may be assessed for their 
correctness otherwise and marks be awarded to them. In class-X, while evaluating two 
competency based questions, please try to understand given answer and even if reply is not 
from marking scheme but correct competency is enumerated by the candidate, marks should 
be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each evaluator on the 
first day, to ensure that evaluation has been carried out as per the instructions given in the Marking 
Scheme. The remaining answer books meant for evaluation shall be given only after ensuring that 
there is no significant variation in the marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  Evaluators 
will not put right kind of mark while evaluating which gives an impression that answer is correct and 
no marks are awarded.  This is most common mistake which evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks awarded for 
different parts of the question should then be totaled up and written in the left-hand margin and 
encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks should 
be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only once. 
10. A full scale of marks  0-35 (example 0-40 marks as given in Question Paper) has to be used. Please 
do not hesitate to award full marks if the answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours every day 
and evaluate 30 answer books per day in main subjects and 35 answer books per day in other 
subjects (Details are given in Spot Guidelines).This is in view of the reduced syllabus and number of 
questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the Examiner in 
the past:- 
Page 2


042_55/1/1_Physics # Page-1 
  
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – PHYSICS (SUBJECT CODE – 042) 
(PAPER CODE – 55/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct assessment 
of the candidates. A small mistake in evaluation may lead to serious problems which may affect the 
future of the candidates, education system and teaching profession. To avoid mistakes, it is 
requested that before starting evaluation, you must read and understand the spot evaluation 
guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to public in 
any manner could lead to derailment of the examination system and affect the life and future 
of millions of candidates. Sharing this policy/document to anyone, publishing in any 
magazine and printing in News Paper/Website etc may invite action under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be done 
according to one’s own interpretation or any other consideration. Marking Scheme should be strictly 
adhered to and religiously followed. However, while evaluating, answers which are based on 
latest information or knowledge and/or are innovative, they may be assessed for their 
correctness otherwise and marks be awarded to them. In class-X, while evaluating two 
competency based questions, please try to understand given answer and even if reply is not 
from marking scheme but correct competency is enumerated by the candidate, marks should 
be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each evaluator on the 
first day, to ensure that evaluation has been carried out as per the instructions given in the Marking 
Scheme. The remaining answer books meant for evaluation shall be given only after ensuring that 
there is no significant variation in the marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  Evaluators 
will not put right kind of mark while evaluating which gives an impression that answer is correct and 
no marks are awarded.  This is most common mistake which evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks awarded for 
different parts of the question should then be totaled up and written in the left-hand margin and 
encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks should 
be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only once. 
10. A full scale of marks  0-35 (example 0-40 marks as given in Question Paper) has to be used. Please 
do not hesitate to award full marks if the answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours every day 
and evaluate 30 answer books per day in main subjects and 35 answer books per day in other 
subjects (Details are given in Spot Guidelines).This is in view of the reduced syllabus and number of 
questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the Examiner in 
the past:- 
042_55/1/1_Physics # Page-2 
  
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is correctly 
and clearly indicated. It should merely be a line. Same is with the X for incorrect answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
13. While evaluating the answer books if the answer is found to be totally incorrect, it should be marked 
as cross (X) and awarded zero (0)Marks. 
  
14. Any unassessed portion, non-carrying over of marks to the title page, or totaling error detected by 
the candidate shall damage the prestige of all the personnel engaged in the evaluation work as also 
of the Board. Hence, in order to uphold the prestige of all concerned, it is again reiterated that the 
instructions be followed meticulously and judiciously. 
 
15. The Examiners should acquaint themselves with the guidelines given in the Guidelines for spot 
Evaluation before starting the actual evaluation. 
 
16. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to the title 
page, correctly totaled and written in figures and words. 
 
17. The Board permits candidates to obtain photocopy of the Answer Book on request in an RTI 
application and also separately as a part of the re-evaluation process on payment of the processing 
charges.  
Page 3


042_55/1/1_Physics # Page-1 
  
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – PHYSICS (SUBJECT CODE – 042) 
(PAPER CODE – 55/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct assessment 
of the candidates. A small mistake in evaluation may lead to serious problems which may affect the 
future of the candidates, education system and teaching profession. To avoid mistakes, it is 
requested that before starting evaluation, you must read and understand the spot evaluation 
guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to public in 
any manner could lead to derailment of the examination system and affect the life and future 
of millions of candidates. Sharing this policy/document to anyone, publishing in any 
magazine and printing in News Paper/Website etc may invite action under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be done 
according to one’s own interpretation or any other consideration. Marking Scheme should be strictly 
adhered to and religiously followed. However, while evaluating, answers which are based on 
latest information or knowledge and/or are innovative, they may be assessed for their 
correctness otherwise and marks be awarded to them. In class-X, while evaluating two 
competency based questions, please try to understand given answer and even if reply is not 
from marking scheme but correct competency is enumerated by the candidate, marks should 
be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each evaluator on the 
first day, to ensure that evaluation has been carried out as per the instructions given in the Marking 
Scheme. The remaining answer books meant for evaluation shall be given only after ensuring that 
there is no significant variation in the marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  Evaluators 
will not put right kind of mark while evaluating which gives an impression that answer is correct and 
no marks are awarded.  This is most common mistake which evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks awarded for 
different parts of the question should then be totaled up and written in the left-hand margin and 
encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks should 
be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only once. 
10. A full scale of marks  0-35 (example 0-40 marks as given in Question Paper) has to be used. Please 
do not hesitate to award full marks if the answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours every day 
and evaluate 30 answer books per day in main subjects and 35 answer books per day in other 
subjects (Details are given in Spot Guidelines).This is in view of the reduced syllabus and number of 
questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the Examiner in 
the past:- 
042_55/1/1_Physics # Page-2 
  
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is correctly 
and clearly indicated. It should merely be a line. Same is with the X for incorrect answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
13. While evaluating the answer books if the answer is found to be totally incorrect, it should be marked 
as cross (X) and awarded zero (0)Marks. 
  
14. Any unassessed portion, non-carrying over of marks to the title page, or totaling error detected by 
the candidate shall damage the prestige of all the personnel engaged in the evaluation work as also 
of the Board. Hence, in order to uphold the prestige of all concerned, it is again reiterated that the 
instructions be followed meticulously and judiciously. 
 
15. The Examiners should acquaint themselves with the guidelines given in the Guidelines for spot 
Evaluation before starting the actual evaluation. 
 
16. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to the title 
page, correctly totaled and written in figures and words. 
 
17. The Board permits candidates to obtain photocopy of the Answer Book on request in an RTI 
application and also separately as a part of the re-evaluation process on payment of the processing 
charges.  
042_55/1/1_Physics # Page-3 
  
MARKING SCHEME 
Senior Secondary School Examination TERM–II, 2022 
PHYSICS   (Subject Code –042) 
[ Paper Code : 55/1/1 ] 
Q. No. EXPECTED ANSWER / VALUE POINTS Marks Total 
Marks 
 SECTION —A   
1.  
 
 
 
 
 
                      n-type                                           p-type 
 
Significance  
n-type semiconductors – small energy gap between donor level and conduction 
band which can be easily covered by thermally excited electrons. 
 
p- type semiconductors - small energy gap between acceptor level and valence 
band  which can be easily covered by thermally excited electrons. 
 
Alternatively 
The conductivity of semiconductor is improved with the creation of donor and 
acceptor levels. 
 
 
 
 
 
 
 
 
½ + ½ 
 
 
 
 
 
 
 
 
 
 
 
½ 
 
 
½ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2 
Energy band diagram                         ½ + ½  
Significance                                               1 
Page 4


042_55/1/1_Physics # Page-1 
  
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – PHYSICS (SUBJECT CODE – 042) 
(PAPER CODE – 55/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct assessment 
of the candidates. A small mistake in evaluation may lead to serious problems which may affect the 
future of the candidates, education system and teaching profession. To avoid mistakes, it is 
requested that before starting evaluation, you must read and understand the spot evaluation 
guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to public in 
any manner could lead to derailment of the examination system and affect the life and future 
of millions of candidates. Sharing this policy/document to anyone, publishing in any 
magazine and printing in News Paper/Website etc may invite action under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be done 
according to one’s own interpretation or any other consideration. Marking Scheme should be strictly 
adhered to and religiously followed. However, while evaluating, answers which are based on 
latest information or knowledge and/or are innovative, they may be assessed for their 
correctness otherwise and marks be awarded to them. In class-X, while evaluating two 
competency based questions, please try to understand given answer and even if reply is not 
from marking scheme but correct competency is enumerated by the candidate, marks should 
be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each evaluator on the 
first day, to ensure that evaluation has been carried out as per the instructions given in the Marking 
Scheme. The remaining answer books meant for evaluation shall be given only after ensuring that 
there is no significant variation in the marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  Evaluators 
will not put right kind of mark while evaluating which gives an impression that answer is correct and 
no marks are awarded.  This is most common mistake which evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks awarded for 
different parts of the question should then be totaled up and written in the left-hand margin and 
encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks should 
be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only once. 
10. A full scale of marks  0-35 (example 0-40 marks as given in Question Paper) has to be used. Please 
do not hesitate to award full marks if the answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours every day 
and evaluate 30 answer books per day in main subjects and 35 answer books per day in other 
subjects (Details are given in Spot Guidelines).This is in view of the reduced syllabus and number of 
questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the Examiner in 
the past:- 
042_55/1/1_Physics # Page-2 
  
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is correctly 
and clearly indicated. It should merely be a line. Same is with the X for incorrect answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
13. While evaluating the answer books if the answer is found to be totally incorrect, it should be marked 
as cross (X) and awarded zero (0)Marks. 
  
14. Any unassessed portion, non-carrying over of marks to the title page, or totaling error detected by 
the candidate shall damage the prestige of all the personnel engaged in the evaluation work as also 
of the Board. Hence, in order to uphold the prestige of all concerned, it is again reiterated that the 
instructions be followed meticulously and judiciously. 
 
15. The Examiners should acquaint themselves with the guidelines given in the Guidelines for spot 
Evaluation before starting the actual evaluation. 
 
16. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to the title 
page, correctly totaled and written in figures and words. 
 
17. The Board permits candidates to obtain photocopy of the Answer Book on request in an RTI 
application and also separately as a part of the re-evaluation process on payment of the processing 
charges.  
042_55/1/1_Physics # Page-3 
  
MARKING SCHEME 
Senior Secondary School Examination TERM–II, 2022 
PHYSICS   (Subject Code –042) 
[ Paper Code : 55/1/1 ] 
Q. No. EXPECTED ANSWER / VALUE POINTS Marks Total 
Marks 
 SECTION —A   
1.  
 
 
 
 
 
                      n-type                                           p-type 
 
Significance  
n-type semiconductors – small energy gap between donor level and conduction 
band which can be easily covered by thermally excited electrons. 
 
p- type semiconductors - small energy gap between acceptor level and valence 
band  which can be easily covered by thermally excited electrons. 
 
Alternatively 
The conductivity of semiconductor is improved with the creation of donor and 
acceptor levels. 
 
 
 
 
 
 
 
 
½ + ½ 
 
 
 
 
 
 
 
 
 
 
 
½ 
 
 
½ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2 
Energy band diagram                         ½ + ½  
Significance                                               1 
042_55/1/1_Physics # Page-4 
  
2(a). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2(b).  
 
 
    
                
                         
 
(Give full credit if axis are marked and values are not given) 
 
Conclusions 
? Most of the alpha particles pass undeviated through the gold foil. 
? A few alpha particles, get deflected through 90° or more. 
? Only about 0.14% of the incident alpha particles are reflected by large 
angle. 
? A very few alpha particles retrace their path.  
 Any other two conclusions  
  
OR 
 
 
 
 
 
 
 
(i)                                                 (ii) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1 
 
 
 
 
 
 
 
 
 
 
½+½ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1+1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2 
Graph                                                                 1 
Conclusions (any two )                                 ½  + ½  
i) Same  intensity different frequency                                 1 
ii) Same frequency different intensity                                 1 
Page 5


042_55/1/1_Physics # Page-1 
  
Strictly Confidential: (For Internal and Restricted use only) 
Senior Secondary School Term II Examination, 2022 
Marking Scheme – PHYSICS (SUBJECT CODE – 042) 
(PAPER CODE – 55/1/1) 
General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct assessment 
of the candidates. A small mistake in evaluation may lead to serious problems which may affect the 
future of the candidates, education system and teaching profession. To avoid mistakes, it is 
requested that before starting evaluation, you must read and understand the spot evaluation 
guidelines carefully. 
2. “Evaluation policy is a confidential policy as it is related to the confidentiality of the 
examinations conducted, Evaluation done and several other aspects. Its’ leakage to public in 
any manner could lead to derailment of the examination system and affect the life and future 
of millions of candidates. Sharing this policy/document to anyone, publishing in any 
magazine and printing in News Paper/Website etc may invite action under IPC.” 
3. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be done 
according to one’s own interpretation or any other consideration. Marking Scheme should be strictly 
adhered to and religiously followed. However, while evaluating, answers which are based on 
latest information or knowledge and/or are innovative, they may be assessed for their 
correctness otherwise and marks be awarded to them. In class-X, while evaluating two 
competency based questions, please try to understand given answer and even if reply is not 
from marking scheme but correct competency is enumerated by the candidate, marks should 
be awarded.   
4. The Head-Examiner must go through the first five answer books evaluated by each evaluator on the 
first day, to ensure that evaluation has been carried out as per the instructions given in the Marking 
Scheme. The remaining answer books meant for evaluation shall be given only after ensuring that 
there is no significant variation in the marking of individual evaluators. 
5. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X’ be marked.  Evaluators 
will not put right kind of mark while evaluating which gives an impression that answer is correct and 
no marks are awarded.  This is most common mistake which evaluators are committing. 
6. If a question has parts, please award marks on the right-hand side for each part. Marks awarded for 
different parts of the question should then be totaled up and written in the left-hand margin and 
encircled.  This may be followed strictly. 
7. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
8. If a student has attempted an extra question, answer of the question deserving more marks should 
be retained and the other answer scored out. 
9. No marks to be deducted for the cumulative effect of an error. It should be penalized only once. 
10. A full scale of marks  0-35 (example 0-40 marks as given in Question Paper) has to be used. Please 
do not hesitate to award full marks if the answer deserves it. 
11. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours every day 
and evaluate 30 answer books per day in main subjects and 35 answer books per day in other 
subjects (Details are given in Spot Guidelines).This is in view of the reduced syllabus and number of 
questions in question paper. 
12. Ensure that you do not make the following common types of errors committed by the Examiner in 
the past:- 
042_55/1/1_Physics # Page-2 
  
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is correctly 
and clearly indicated. It should merely be a line. Same is with the X for incorrect answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
13. While evaluating the answer books if the answer is found to be totally incorrect, it should be marked 
as cross (X) and awarded zero (0)Marks. 
  
14. Any unassessed portion, non-carrying over of marks to the title page, or totaling error detected by 
the candidate shall damage the prestige of all the personnel engaged in the evaluation work as also 
of the Board. Hence, in order to uphold the prestige of all concerned, it is again reiterated that the 
instructions be followed meticulously and judiciously. 
 
15. The Examiners should acquaint themselves with the guidelines given in the Guidelines for spot 
Evaluation before starting the actual evaluation. 
 
16. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to the title 
page, correctly totaled and written in figures and words. 
 
17. The Board permits candidates to obtain photocopy of the Answer Book on request in an RTI 
application and also separately as a part of the re-evaluation process on payment of the processing 
charges.  
042_55/1/1_Physics # Page-3 
  
MARKING SCHEME 
Senior Secondary School Examination TERM–II, 2022 
PHYSICS   (Subject Code –042) 
[ Paper Code : 55/1/1 ] 
Q. No. EXPECTED ANSWER / VALUE POINTS Marks Total 
Marks 
 SECTION —A   
1.  
 
 
 
 
 
                      n-type                                           p-type 
 
Significance  
n-type semiconductors – small energy gap between donor level and conduction 
band which can be easily covered by thermally excited electrons. 
 
p- type semiconductors - small energy gap between acceptor level and valence 
band  which can be easily covered by thermally excited electrons. 
 
Alternatively 
The conductivity of semiconductor is improved with the creation of donor and 
acceptor levels. 
 
 
 
 
 
 
 
 
½ + ½ 
 
 
 
 
 
 
 
 
 
 
 
½ 
 
 
½ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2 
Energy band diagram                         ½ + ½  
Significance                                               1 
042_55/1/1_Physics # Page-4 
  
2(a). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2(b).  
 
 
    
                
                         
 
(Give full credit if axis are marked and values are not given) 
 
Conclusions 
? Most of the alpha particles pass undeviated through the gold foil. 
? A few alpha particles, get deflected through 90° or more. 
? Only about 0.14% of the incident alpha particles are reflected by large 
angle. 
? A very few alpha particles retrace their path.  
 Any other two conclusions  
  
OR 
 
 
 
 
 
 
 
(i)                                                 (ii) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1 
 
 
 
 
 
 
 
 
 
 
½+½ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1+1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2 
Graph                                                                 1 
Conclusions (any two )                                 ½  + ½  
i) Same  intensity different frequency                                 1 
ii) Same frequency different intensity                                 1 
042_55/1/1_Physics # Page-5 
  
3.  
 
 
The unidirectional property of a diode makes it suitable for rectification. 
Alternatively 
The diode conducts when forward biased and does not conduct when reverse 
biased. 
(Award 1 mark if a student draws the forward and reverse characteristics 
of a diode.) 
 
 
 
 
2 
 
 
 
 
 
 
 
2 
 SECTION- B   
4. 
 
 
The minimum distance up to which an alpha particle travel along the central 
line of the nucleus before it rebounds is called distance of closest approach. 
Alternatively 
An alpha particle travelling directly towards the centre of a nucleus slows 
down as it approaches the nucleus due to repulsive force. At a distance r
0 
from 
the nucleus, the a- particle stops and its total kinetic energy converts into 
electrostatic potential energy. This distance r
0 
is called distance of closest 
approach. 
2
0
0
2
4 . .
Ze
r
KE
?
??
 
i.e., 
0
1
..
r
KE
? 
as K is doubled ,  r
0 
is halved. 
(Award full 1½ marks if a student writes r
0
 is halved without writing 
formula) 
 
 
1 ½ 
 
 
 
 
 
½ 
 
 
½  
 
½ 
 
 
 
 
 
 
 
 
 
 
 
 
 
3 
5.  
 
 
Relation for concave spherical surface 
  
1 2 2 1
v uR
? ? ? ? ?
??
?
 
  
11
v uR
? ? ?
??
?
 
  
1 1 5 1 5 1
( 24) v 60
? ? ?
??
? ? ?
 
 
v 30 cm ? ? ? 
 
 
 
 
 
½ 
 
½ 
 
½ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Explanation                                                      2 
Definition of distance of closest approach                                     1 ½  
Effect on distance of closest approach due to change in K.E.       1 ½  
 
Finding distance from source                                                2  
Finding nature of image                                                        1