ANSWERS
OBJECTIVE LEVEL – I
1. (d) 2. (b)
3. (c) 4. (c)
5. (c) 6. (c)
7. (b) 8. (a)
9. (c) 10. (d)
11. (b) 12. (b)
13. (b) 14. (b)
15. (d)
OBJECTIVE LEVEL – II
1. (d) 2. (d)
3. (c) 4. (a)
5. (a) 6. (c)
7. (b) 8. (a)
9. (c) 10. (a)
11. (d) 12. (c)
13. (b) 14. (b)
15. (d)
(C.B.S.E.) LEVEL - I
1. 17 , 8.5V

2. (a) 6 (b) 2V, 4V, 6V

3. 12 V
4. 30 A
5. (a) X = 8.2  ; to minimise reistance of the connection which are not accounted for in
the bridge formula
(b) 60.5 cm From A
(c) The galvanometer will show no current
6. Resistance in series = 5988 .
7. 2.25 V
8. 4
2.7 10
 s (7.5 Hrs)
9. 11 Volt, 9 Volt, 6 Volt
10. (a) 1.4 A, 11.9 V
(b) 0.005 A 5 mA

11. (a) (i) in series (ii) all in parallel ; n2
(b) (i) join 1 , 2  in parallel and the combination in series with 3 .
(ii) parallel combination of 2 and 3  in series with 1 .
(iii) all in series.
(iv) all in parallel.
(c) (i) 16/3  (ii) 5R
12. 3.7 A
13. (a) The 20K voltmeter gives the highest reading; the last case (both the voltmeters
across AB) gives the lowest reading.
(b) All cases will give the same reading if internal resistance is zero; otherwise answer
is similar to (a).
14. Reading will be same for all times
15. (a) 10  (b) 2 
SUBJECTIVE LEVEL - II
1. 7
2. (a) 2/13 V (b) Across G 21/13 V
Across H 19/13 V

3.
t
R 2
Cln3
  
4. (a)
4
r
3
(b)
r
4
.
5. 0 Amp
6. 4/9 Amp, 2W
7. 1 2
4
R (r r )
7
 
8.
72
r ; E 19V
19
  
9. Number of time constnat is ln 2
10. 40 V
SUBJECTIVE LEVEL - III
1. (a) 32 (b) 20 V
(c) No change
2. (i) 0.5 A (ii) 0.833 A
(iii) 1.7 V
3. (a) 2 V (b) 6 Amp
(c)
1
3

4.
R=100
R=10
6

R=10
-3

G
G
Voltmeter
Ammeter
5. 11 mA

6.
0
t
k
0
Q
e
k

 
 
7.
L W
R
A AY

 
   
 
= 0.22
8. (a) 0.9 A (b) 0.00494 A, 1.97 V
9. (b)
b a
2
b a
r r
V
J
r r r
 
  
 
 
10. 2
1 VC
EC 1
e e
 
 
 
 
PROBLEMS
1. (a) No (b) A D
B C
12
X
G
J
(c) 8
2. (i) A C
q 90 C, q 210 C
    and B
q 150 C
 
(ii) (a) 47.4 mJ. (b) Uf
= 18 mJ.
3.
20
V
3