2016 - JAMB Physics Past Questions and Answers - page 5
41
Boiling occurs when the vapour pressure of a liquid is
A
At the evaporation point
B
Less than the atmospheric pressure
C
Greater than the atmospheric pressure
D
Equal to the atmospheric pressure
correct option: d
Users' Answers & Comments42
If the magnification of a virtual image formed by an object 10cm from a convex less is 3, then the focal length of the lens is
A
10cm
B
20cm
C
25cm
D
15cm
correct option: d
M = \(\frac{v}{u}\) = 3 = \(\frac{v}{30}\). V = 30m
\(\frac{1}{u}\) + \(\frac{1}{v}\) = \(\frac{1}{f}\) = \(\frac{1}{10}\) - \(\frac{1}{30}\) = \(\frac{1}{f}\)
\(\frac{3 - 1}{30}\) = \(\frac{1}{f}
f = \(\frac{30}{2}\) = 15cm
Users' Answers & Comments\(\frac{1}{u}\) + \(\frac{1}{v}\) = \(\frac{1}{f}\) = \(\frac{1}{10}\) - \(\frac{1}{30}\) = \(\frac{1}{f}\)
\(\frac{3 - 1}{30}\) = \(\frac{1}{f}
f = \(\frac{30}{2}\) = 15cm
43
An electron in a hydrogen atom makes a transition from the ground level to the third level. If the energy at the ground level,calculate the energy at the third level.
[h = 6.6 x 10-34Js; f = 1015Hz]
[h = 6.6 x 10-34Js; f = 1015Hz]
A
1.41eV
B
1.71eV
C
1.61eV
D
1.51eV
correct option: d
E = \(\frac{E_o}{n^2}\) = \(\frac{13.6}{3^2}\) = \(\frac{13.6eV}{9}\)
= 1.51eV
Users' Answers & Comments= 1.51eV
44
A
C
B
D
C
B
D
A
correct option: c
Users' Answers & Comments
46
A
4.78mm
B
4.16mm
C
4.66mm
D
4.70mm
correct option: b
Users' Answers & Comments47
A
MP
B
SN
C
NS
D
PM
correct option: c
Users' Answers & Comments48
Which of the following statements is Not true about atoms?
A
Atom of different elements have different atomic weights
B
The mass of an atom is concentrated in the nucleus
C
An atom is made up of a nucleus and number of electrons
D
Atoms of all elements are identical
correct option: d
Users' Answers & Comments49
The frequency of beats produced when two tunning forks of frequencies 258Hz and 270Hz are sounded close to each other
A
6Hz
B
264Hz
C
528Hz
D
12Hz
50
Calculate the inductance of a coil of resistance 30\(\Omega\) connected to a 100V a.c source if the coil draws an r.m.s current of 2A
A
0.60H
B
2.50H
C
1.25H
D
0.04H
correct option: d
Users' Answers & Comments