Page 1
1
Class -XII
PHYSICS
SQP Marking Scheme
2019-20
Section – A
1. a , ?= (for one face) 1
2. b , Conductor 1
3. a , 1?. 1
4. c ,12.0kJ 1
5. a , speed 1
6. d, virtual and inverted 1
7. a, straight line 1
8. d, 60
O
1
9. b, work function 1
10. b, third orbit 1
11. 45
O
or vertical 1
12. 2 H 1
13. double 1
14. 1.227 A
o
1
15. 60° 1
16. Difference in initial mass energy and energy associated with mass of products
Or
Total Kinetic energy gained in the process
1
17. Increases 1
18. N o/8 1
19. 0.79 eV 1
20. Diodes with band gap energy in the visible spectrum range can function as LED 1
Page 2
1
Class -XII
PHYSICS
SQP Marking Scheme
2019-20
Section – A
1. a , ?= (for one face) 1
2. b , Conductor 1
3. a , 1?. 1
4. c ,12.0kJ 1
5. a , speed 1
6. d, virtual and inverted 1
7. a, straight line 1
8. d, 60
O
1
9. b, work function 1
10. b, third orbit 1
11. 45
O
or vertical 1
12. 2 H 1
13. double 1
14. 1.227 A
o
1
15. 60° 1
16. Difference in initial mass energy and energy associated with mass of products
Or
Total Kinetic energy gained in the process
1
17. Increases 1
18. N o/8 1
19. 0.79 eV 1
20. Diodes with band gap energy in the visible spectrum range can function as LED 1
2
OR
Any one use
Section – B
21. When electric field E is applied on conductor force acting on free electrons
= -e
m = -e
=
Average thermal velocity of electron in conductor is zero
(u t) av= 0
Average velocity of electron in conductors in t (relaxation time) = v d (drift velocity)
v d = (u t) av + a t
v d = 0 +
=
1
1
22.
C 2 and C 3 are in series
= + = 1
= 1µf
& C 4 are in ?
C” = 1 + 1 = 2µf
C” & c 5 are in series
= + ? = 1µf
& c 1 are in ?
C eq = 1 + 1 = 2µf
Energy stored
U = cv
2
= ×2×10
-6
×6
2
= 36×10
-6
J
1
1
Page 3
1
Class -XII
PHYSICS
SQP Marking Scheme
2019-20
Section – A
1. a , ?= (for one face) 1
2. b , Conductor 1
3. a , 1?. 1
4. c ,12.0kJ 1
5. a , speed 1
6. d, virtual and inverted 1
7. a, straight line 1
8. d, 60
O
1
9. b, work function 1
10. b, third orbit 1
11. 45
O
or vertical 1
12. 2 H 1
13. double 1
14. 1.227 A
o
1
15. 60° 1
16. Difference in initial mass energy and energy associated with mass of products
Or
Total Kinetic energy gained in the process
1
17. Increases 1
18. N o/8 1
19. 0.79 eV 1
20. Diodes with band gap energy in the visible spectrum range can function as LED 1
2
OR
Any one use
Section – B
21. When electric field E is applied on conductor force acting on free electrons
= -e
m = -e
=
Average thermal velocity of electron in conductor is zero
(u t) av= 0
Average velocity of electron in conductors in t (relaxation time) = v d (drift velocity)
v d = (u t) av + a t
v d = 0 +
=
1
1
22.
C 2 and C 3 are in series
= + = 1
= 1µf
& C 4 are in ?
C” = 1 + 1 = 2µf
C” & c 5 are in series
= + ? = 1µf
& c 1 are in ?
C eq = 1 + 1 = 2µf
Energy stored
U = cv
2
= ×2×10
-6
×6
2
= 36×10
-6
J
1
1
3
23. Gain in KE of particle = Qv
= K P = q pV p ----------(i)V p = V ? =V
= K ? = q ?V ? -----------(ii)
(ii)/(i)
= =
= = =
v ? : v p = 1:
1
1
24. “The angle of incidence at which the reflected light is completely plane
polarized, is called as Brewster’s angle (i B)
At i = i B, reflected beam 1 to refracted beam
? i B + r = 90 ? r = 90-i B
Using snell’s law
= µ
= µ ? = µ
µ = tan
1
1
25. wave function
? = 2.14eV
(a) Threshold frequency ? = h? 0
? 0 = =
1
Page 4
1
Class -XII
PHYSICS
SQP Marking Scheme
2019-20
Section – A
1. a , ?= (for one face) 1
2. b , Conductor 1
3. a , 1?. 1
4. c ,12.0kJ 1
5. a , speed 1
6. d, virtual and inverted 1
7. a, straight line 1
8. d, 60
O
1
9. b, work function 1
10. b, third orbit 1
11. 45
O
or vertical 1
12. 2 H 1
13. double 1
14. 1.227 A
o
1
15. 60° 1
16. Difference in initial mass energy and energy associated with mass of products
Or
Total Kinetic energy gained in the process
1
17. Increases 1
18. N o/8 1
19. 0.79 eV 1
20. Diodes with band gap energy in the visible spectrum range can function as LED 1
2
OR
Any one use
Section – B
21. When electric field E is applied on conductor force acting on free electrons
= -e
m = -e
=
Average thermal velocity of electron in conductor is zero
(u t) av= 0
Average velocity of electron in conductors in t (relaxation time) = v d (drift velocity)
v d = (u t) av + a t
v d = 0 +
=
1
1
22.
C 2 and C 3 are in series
= + = 1
= 1µf
& C 4 are in ?
C” = 1 + 1 = 2µf
C” & c 5 are in series
= + ? = 1µf
& c 1 are in ?
C eq = 1 + 1 = 2µf
Energy stored
U = cv
2
= ×2×10
-6
×6
2
= 36×10
-6
J
1
1
3
23. Gain in KE of particle = Qv
= K P = q pV p ----------(i)V p = V ? =V
= K ? = q ?V ? -----------(ii)
(ii)/(i)
= =
= = =
v ? : v p = 1:
1
1
24. “The angle of incidence at which the reflected light is completely plane
polarized, is called as Brewster’s angle (i B)
At i = i B, reflected beam 1 to refracted beam
? i B + r = 90 ? r = 90-i B
Using snell’s law
= µ
= µ ? = µ
µ = tan
1
1
25. wave function
? = 2.14eV
(a) Threshold frequency ? = h? 0
? 0 = =
1
4
= 5.17× H z
(b) As k max = eV 0 = 0.6eV
Energy of photon E = k max + ? = 0.6eV + 2.14eV
= 2.74eV
Wave length of photon ? = =
= 4530Å
1
26.
centripetal force = electrostatic attraction
=
= --------(i)
as = n .
= put in (i)
m . =
=
OR
Energy of electron in n = 2 is -3.4eV
? energy in ground state = -13.6eV
kE = -TE = +13.6eV
1
1
1
E n = ? -3.4eV = ?
energy in ground state x = - 13.6eV.
Page 5
1
Class -XII
PHYSICS
SQP Marking Scheme
2019-20
Section – A
1. a , ?= (for one face) 1
2. b , Conductor 1
3. a , 1?. 1
4. c ,12.0kJ 1
5. a , speed 1
6. d, virtual and inverted 1
7. a, straight line 1
8. d, 60
O
1
9. b, work function 1
10. b, third orbit 1
11. 45
O
or vertical 1
12. 2 H 1
13. double 1
14. 1.227 A
o
1
15. 60° 1
16. Difference in initial mass energy and energy associated with mass of products
Or
Total Kinetic energy gained in the process
1
17. Increases 1
18. N o/8 1
19. 0.79 eV 1
20. Diodes with band gap energy in the visible spectrum range can function as LED 1
2
OR
Any one use
Section – B
21. When electric field E is applied on conductor force acting on free electrons
= -e
m = -e
=
Average thermal velocity of electron in conductor is zero
(u t) av= 0
Average velocity of electron in conductors in t (relaxation time) = v d (drift velocity)
v d = (u t) av + a t
v d = 0 +
=
1
1
22.
C 2 and C 3 are in series
= + = 1
= 1µf
& C 4 are in ?
C” = 1 + 1 = 2µf
C” & c 5 are in series
= + ? = 1µf
& c 1 are in ?
C eq = 1 + 1 = 2µf
Energy stored
U = cv
2
= ×2×10
-6
×6
2
= 36×10
-6
J
1
1
3
23. Gain in KE of particle = Qv
= K P = q pV p ----------(i)V p = V ? =V
= K ? = q ?V ? -----------(ii)
(ii)/(i)
= =
= = =
v ? : v p = 1:
1
1
24. “The angle of incidence at which the reflected light is completely plane
polarized, is called as Brewster’s angle (i B)
At i = i B, reflected beam 1 to refracted beam
? i B + r = 90 ? r = 90-i B
Using snell’s law
= µ
= µ ? = µ
µ = tan
1
1
25. wave function
? = 2.14eV
(a) Threshold frequency ? = h? 0
? 0 = =
1
4
= 5.17× H z
(b) As k max = eV 0 = 0.6eV
Energy of photon E = k max + ? = 0.6eV + 2.14eV
= 2.74eV
Wave length of photon ? = =
= 4530Å
1
26.
centripetal force = electrostatic attraction
=
= --------(i)
as = n .
= put in (i)
m . =
=
OR
Energy of electron in n = 2 is -3.4eV
? energy in ground state = -13.6eV
kE = -TE = +13.6eV
1
1
1
E n = ? -3.4eV = ?
energy in ground state x = - 13.6eV.
5
PE = 2TE = -2×13.6eV = -27.2eV
1
27.
P-type semiconductor n-type semiconductor
1. Density of holes >> density of
electron
2. Formed by doping trivalent
impurity
1. density of
electron>>density of holes
2. formed by doping pentavalent
impurity
Energy band diagram for p-type
Energy band diagram of n-type
semiconductor
OR
Energy of photon E = = eV =2.06eV
As E<E g (2.8eV), so photodiode cannot detect this photon.
Any
2x1
=1
1
1
Section – C
28.
Principle of potentiometer, when a constant current flows through a wire of uniform
area of cross-section, the potential drop across any length of the wire is directly
proportional to the length.
Let resistance of wire AB be R 1 and its length be ‘l’ then current drawn from
driving cell –
I = and hence
P.D. across the wire AB will be
V AB = IR 1 = ×
Where ‘a’ is area of cross-section of wire AB
? = = constant = k
Where R increases, current and potential difference across wire AB will be
1
1
1
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