1992 - JAMB Physics Past Questions and Answers - page 2
11
In A.C circuit theory, the root means square (r.m.s) current, Irms and the peak (maximum)current Io are related by
A
Io = \(\frac{I_rms}{\sqrt{2}}\)
B
Irms = \(\frac{I_o}{\sqrt{2}}\)
C
Irms = \(\frac{\frac{I}{I_o}}{\sqrt2}\)
D
Irms = \(\frac{I_rms}{\sqrt{2}}\)
correct option: b
Users' Answers & Comments12
The threshold of frequency for photoelectric effect depends on the
A
intensity of incident light
B
frquency of incident light
C
material of the photocathode
D
potential difference between the cathode and the anode
correct option: c
Users' Answers & Comments13
After three half lifes, the fraction of a radioactive material that has decayed is
A
\(\frac{1}{8}\)
B
\(\frac{1}{3}\)
C
\(\frac{2}{3}\)
D
\(\frac{7}{8}\)
correct option: d
I = \(\frac{1}{2}\) \(\Rightarrow\) \(\frac{1}{4}\) \(\Rightarrow\) \(\frac{1}{8}\)
Fraction decayed = 1 - \(\frac{1}{8}\)
= \(\frac{7}{8}\)
Users' Answers & CommentsFraction decayed = 1 - \(\frac{1}{8}\)
= \(\frac{7}{8}\)
14
\(^{27}_{13}Al\) + \(^{1}_{0}n\) \(\Rightarrow\) \(^{24}_{11}Na\) + X
A
a proton
B
a gamma ray
C
a helium particle
D
an alpha particle
correct option: d
\(^{27}_{13}Al\) + \(^{1}_{0}n\) \(\Rightarrow\) \(^{24}_{11}Na\) + \(^{b}_{a}X\)
a + 11 = 0 + 13 \(\Rightarrow\) a = 2
b + 24 = 1 + 27 \(\Rightarrow\) b = 4
\(^{b}_{a}X\) = \(^{4}_{2}\alpha\)
Users' Answers & Commentsa + 11 = 0 + 13 \(\Rightarrow\) a = 2
b + 24 = 1 + 27 \(\Rightarrow\) b = 4
\(^{b}_{a}X\) = \(^{4}_{2}\alpha\)
15
A
F1 + F2 = F3 + F4
B
F1 + F2 - F3 + F = 0
C
(F1 + F2)ab = (F3 + F4)cd
D
F1a + F2b - F3c - F4d = 0
correct option: d
Users' Answers & Comments16
A
m1/m2
B
m1g/m2
C
m2/m1
D
m2g/m1
correct option: c
Users' Answers & Comments17
A
1/3
B
2/3
C
3
D
6
correct option: c
Users' Answers & Comments18
A
S-S poles
B
S-N poles
C
N-S poles
D
N-N poles
correct option: a
Users' Answers & Comments19
A
1.2Ω
B
1.3Ω
C
3.0Ω
D
6.0Ω
correct option: c
Users' Answers & Comments20
A
The reading of W is equal to that of Y and twice that of X
B
The reading of Y is greater than that of Z
C
The readings of W and Y are equal and each is greater than that of X
D
The reading of Z is equal to the sum of the readings of Y and W
correct option: c
Users' Answers & Comments