2019 - JAMB Physics Past Questions and Answers - page 1

The factors that affect the friction between two surfaces are the weight of the object and the coefficient of friction of the surface. I

The interpretation of this shows that solid friction is affected by:

• The surface on which the object is moved or the nature of the surface. i.e., rough surface, smooth surface, liquids etc.
• The weight of the object or the amount of force on the surface by the object.

Since velocity is a vector that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity. For this reason, it can be safely concluded that an object moving in a circle at constant speed is indeed accelerating.

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When green and blue lights mix, the result is a cyan. When the blue and red lights mix, the result is magenta. Red–green–blue additive mixing is used in television and computer monitors, including smartphone displays, to produce a wide range of colors. A screen pixel uses a juxtaposition of these three primary colors.

via wikipedia

L\(_1\) = 100cm,

T\(_1\) = 200\(^o\)C

L\(_2\) = 99.4cm,

T\(_2\) = ?

\(\alpha\) = 2 x 10\(^{-5}\)C\(^{-1}\)

\(\alpha\) = \(\frac{L_2 - L_1}{L_1(T_2 - T_1)}\)

2 x 10\(^{-5} = \frac{100- 99.4}{100(200 - T_2)} = \frac{0.6}{100(200 - T_2)}\)

2 x 10\(^{-5}\) x \(100(200 - T_2) = 0.6\)

\(200 - T_2 = \frac{0.6}{0.002} = 300^oC\)

\(T_2 = 200 - 300 = -100^oC\)

In kinetic molecular theory, the gases are energised and hence moves freely and energetically as they occupy specific space. 

Kinetic Molecular Theory states that gas particles are in constant motion and exhibit perfectly elastic collisions. Kinetic Molecular Theory can be used to explain both Charles' and Boyle's Laws. The average kinetic energy of a collection of gas particles is directly proportional to absolute temperature only.

via courses.lumenlearning.com

Formula:

Tsin30 + Tsin30 = 40

2Tsin30 = 40

Tsin30 = 40/2 = 20

T(\(\frac{1}{2}\)) = 20

T = 20 x 2

T = 40N

V = u - at,

at u = 44m/s,

44 + [-4]10

4m/s

The arrangement of the lamps in lightenings is such that heat losses are reduced. The resultant resistance is small for a parallel arrangement which means there is low heat losses: [Heat \(\alpha\) R]

The change from the solid-state to the liquid state is called melting. The temperature at which a substance changes from a solid to a liquid is called the melting point. During this transformation process from the solid to the liquid state, there is no production of temperature increase due to the heat supplied because all the heat is used to break the bonds holding the molecules of the solid together

\(\frac{R}{3.6} = \frac{75}{25} = \frac{1}{3}\)

3R = 3.6

R = 1.2\(\Omega\)

Answer: 1.2\(\Omega\)