2007 - JAMB Physics Past Questions and Answers - page 3

In general, electric field strength E = (F)/q

(qq)/4RE₀ V²

∴if E₁ = 360 NC-1 F = q₁ E₁ = q₂E₂
E₂ = (q₁E₁)/q₂
∴ E₂ = (50 X 10^-6 X 360)/120 X 10^-6 = 150 NC ^-1

E = HF = (hc)/λ
Eλ = hc
∴ X = hc ==6.63 x 10^-34 x 10⁸
= 1.989 x 10^-25
=1.99 x 10^-25

When silicon, a four valency element, is doped with aluminum, a three valency element, a p-type semiconductor is produced where the major carriers are the electrons.
Thus, the correct option is p-type and n-type respectively

Resolution of force:
Total vertical upward force:
= 3√3 + 10 cos 60^o
= 3√3 + 5.
Total downward force
= 6 cos 30^o
= 6 x √(³/₂) = 3√3
Total horizontal forces towards right;
= 3N + cos 30^o
= 3N + 10 x √(³/₂)
= 3N + 5√3
Total horizontal forces towards left:
= 6 cos 60^o
= 6 x 0.5
= 3.0N
Summary:
Vertical resultant forces upward:
= 3√3 + 5 - 3√3
= 5N
Horizontal resultant forces towards right:
= 3N + 5√3 - 3√3
= 5N
Horizontal resultant force towards right
= 3N + 5√3 - 3N
= 5√3N

∴ R² = 5² + (5√3)²
= 25 + 25 x 3
= 100
∴ R = √100
= 10N

The ball has its fastest speed at its equilibrium position when its displacement X = O; at X

Being a uniform rod, the height W should be acting at the mid point 25cm mark.
∴ Taking moment about the fulcrum, F,
200 x 10 = W x 10 + 40 x 30
2000 = 10W + 1200
=> 10W = 2000 - 1200
= 800
w = 800/10 = 80N

Effective component of the force along the horizontal = F cos 60^o
Work done by this force : 60
F cos 60 x X
= 2 x 0.5 x 3
= 3J

If the lineal expansivity = ∝
=> area expansivity β= 2∝.
And cubic expansivity δ = 3∝.
=> 6.3 x 10^-6 = 3∝
∴ ∝ =

∴ ∝ =	6.3 x 10-6	= 2.1x 10-6
__3

∴ Area = 2∝ = 2 x 2.1x10^-6
= 4.2 x 10^-6K^-1

Ratio of their linear expansion = ^∝₁/_∝2= 3:4.
When heated to the same temperature range, the ratio of their increase in length ^e₁/_e2 = 1:2
But the increase in length of
1 = e₁ = ∝₁l₁Δθ and increase i length of
2 = e₂ = ∝₂l₂Δθ

=>	e1	=	∝1l1Δθ	=	∝1l1	=	1
e2	∝2l2Δθ	∝2l2	2

But	∝1	=	3	, ∴	3	x	l1	=	1
∝2	4	4	l2	2

=> 6l₁ = 4l₂

∴	l1	=	4	=	2	OR 2 : 3
l2	6	3