2009 - JAMB Physics Past Questions and Answers - page 1
The leaves collapse as the position charges on the rod neutralize the negative charges on the electroscope
Users' Answers & CommentsPrimary colours are red, blue and green
∴ orange is a secondary colour
Users' Answers & CommentsThe leaves collapse as the positive charges on the rod neutralize the negative charges on the electroscope.
Users' Answers & CommentsEnergy generated = power X time = 60w x 1h = 60 x 60 x 60 ws = 216000j = 2.16 x 105J
Users' Answers & CommentsNumber of tunes, n = 500
Area, A = 0.2m + 0.2m = 0.4m2
change of flux density A B
= 1.0 - 0.4 = 0.6T
Tune, t = 5 su
Induced emf, ξ = (AB AN)/AT
(0.6 x 0. 04 x 500)/5
= 2.4v
Users' Answers & CommentsCanorous cells can be destroyed with a high penetrating radiation which is x - rays
Users' Answers & CommentsIf the half life of the material is 20 seconds, the number of disintegration in the first second is
The number of disintegration,∆N in time interval At, is given by
- ∆N = N∆t
Where N is the number of atoms present at the time t
But ^ = (0.693)/T
∴ ∆N = (0.693)/1(1)/2 N∆t = (0.693 x 10)20 x 10/20 = 3.47 x 1018
Users' Answers & CommentsThermionic emission is ejection of electron from a metal surface as a result of heating.
Users' Answers & CommentsMetals are good conductors due to the presence of free electrons
Users' Answers & Comments