JAMB Physics Past Questions & Answers - Page 461

2,301.

2311Na + Proton → pqX + alpha particle
What are the values of p and q respectively in the equation above?

A.

10 and 20

B.

12 and 24

C.

20 and 10

D.

24 and 12

Correct answer is C

2311Na + Proton → pqX + alpha particle
Represent;
2311Na + 11P → pqX + 42He

Thus from the above equations, p = 20 and q = 10

2,302.

In the Rutherford scattering experiment, a beam of alpha particles was fired at a thin gold film with some of the particles being considerably deflected. This shows that

A.

a gold nucleus contains protons, neutrons and electrons uniformly distributed in a tiny volume

B.

the gold nucleus is positively charged and is concentrated in a tiny volume

C.

the gold nucleus emitted alpha particles

D.

the gold nucleus is concentrated in a tiny volume and contains alpha particles

Correct answer is B

No explanation has been provided for this answer.

2,303.

in a series R-L-C circuit at resonance, the voltages across the resistor and the inductor are 30V and 40V respectively, what is the voltage across the capacitor?

A.

30V

B.

40V

C.

50V

D.

70V

Correct answer is B

At resonance, inductive reactant XL is equal to the capacitive reactance XC
i.e. XL = XC
and XL = VL/IL
and XC = VC/IC

Again since the components are in series, the same current flows in the series arrangment
i.e. IL = IC
at resonance, VL/IL = VC/IC
∴ VL = VC
= 40V

2,304.

What is the speed of a particle of mass 10-27kg whose wavelength is 10-8m.

[h = 6.63 x 10-34Js]

A.

6.63ms-1

B.

66.30ms-1

C.

663.00ms-1

D.

6630.00ms-1

Correct answer is B

Energy of a particle is given by
E = hf = hV/λ (since V = fxλ)
But in terms of mass M, E = ∆MV2
∴ ∆MV2 = hV/λ
∆MV = h/λ
∴ V = h/λ∆M
V = 6.63 x 10-34/(10-27 x 10-8)
V = 6.63 x 10-34/10-35
V = 6.63 x 10-34+35
V = 6.63 x 10
V = 66.3ms-1

2,305.

Gamma rays are produced when

A.

high velocity electrons are abruptly stopped in metals

B.

energy changes occur within the nucleus of atoms

C.

energy changes occur within the electronic structure of atoms

D.

electrons are deflected in very strong magnetic fields

Correct answer is B

Gamma rays are electromagnetic radiation of nuclear origin; they are produced from energy changes which occur within the nucleus of ato