2007 - JAMB Physics Past Questions and Answers - page 3

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

              (qq)/4RE<sub>0</sub> V<sup>2</sup><br />

∴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∝

∴ ∝ =

∴ 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

=> 6l₁ = 4l₂