"Modern Physics and Introductory Electronics" question number distribution across years

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JAMB questions for "Physics :: Modern Physics and Introductory Electronics"

Q1

The bond that forms a semiconductor is

A

ionic

B

metallic

C

electrovalent

D

covalent

E

Q2

During the nuclear reactions described by 235/92 W ---> 235/93 X ---> 231/91 Y , the particles emitted are respectively.

A

β and α

B

α and α

C

α and β

D

β and β

E

Q3

A photon of wavelength 6.0 x 10^{-7} m behaves like a particle of a certain mass. The value of that mass is

A

1.1 x 10^{-35} kg

B

3.5 x 10^{-36} kg

C

2.2 x 10^{-27} kg

D

2.2 x 10^{-35} kg

E

Q4

Solicon doped with aluminium and germanium doped with arsenic become

A

p - type semiconductors

B

n - type semiconductors

C

p - and n - types respectively

D

n - and p- types respectively

E

Q5

The energy E of a photon and its wavelength are related E λ = X. The numerical valve of X is

A

6.60 x 10^{-26}

B

1.99 x 10^{-25}

C

1.99 x 10^{-27}

D

6.60 x 10^{-28}

E

Q6

A radioactive substance has a half-life of 20 days. What fraction of the original radioactive nuclei will remain after 80 days ?

A

1/4

B

1/8

C

1/16

D

1/32

E

Q7

One of the properties of gamma rays is that they are

A

massive

B

neutral

C

negatively charged

D

positively charged

E

Q8

I. The number of neutrons released exceeds the number that caused the fission
II. There is loss of mass
III. Energy is produced
IV. Smaller nuclei merge to form larger nuclei
Which of the statements above is correct about nuclear fission?

A

I, III and IV only

B

II, III and IV only

C

I ,II and IV only

D

I, II and III only

E

Q9

A certain manufacturer wishes to make an n-type semiconductor. Which materials would he select for dropping ?

A

Aluminium and indium

B

Arsenic and antimony

C

Boron and antimony

D

helium and boron

E

Q10

A radioactive element has a half life of 4 days. The fraction that has decayed in 16 days is

A

1/4

B

15/16

C

3/4

D

1/16

E

Q11

The process through which free electrons leave the surface of hot metals in known as

A

Photo emission

B

thermionic emission

C

electron emission

D

photon emission

E

Q12

The theory of electronic conduction in solids, which satisfactorily explains the properties of conductors, insulators and semiconductors, is

A

string theory

B

group theory

C

band theory

D

particle theory

E

Q13

The energy associated with the emitted photon when a mercury atom changes from one state to another is 3.3 eV. Calculate the frequency of photon

A

3.1 X 10^{52}Hz

B

8.0 X 10^{14}Hz

C

1.3 X 10^{-15}Hz

D

3.2 X 10^{-53}Hz

E

Q14

When impurities are added to semi-conductors, the conductivity of the semi-conductor

A

remains constant

B

increases then decreases

C

increases

D

decrease

E

Q15

The ray which causes gas molecules to glow is known as

A

molecular ray

B

gamma ray

C

anode ray

D

cathode ray

E

Q16

A silicon material is dropped with an element of a certain group and an n-type semi-conductor is formed. The most likely group of the element is

A

II

B

I

C

V

D

III

E

Q17

The time it will take a certain radioactive material with a half-life of 50 days to reduce to 1/32 of its original number is

A

300 days

B

150 days

C

200 days

D

250 days

E

Q18

In the reaction above, X is

A

neutron

B

electron

C

neutrino

D

proton

E

Q19

A radioisotope has a decay constant of 10^{-7}s^{-1}. The average life of the radioisotope is

A

1.00 x 10^{7}s

B

6.93 x 10^{8}s

C

1.00 x 10^{-7}s

D

6.93 x 10^{7}s

E

Q20

For semiconductors to have negative temperature coefficient of resistance implies that

A

their resistance decreases with temperature

B

their resistance increases with temperature

C

their resistance is constantly changing with temperature

D

they have electrons and holes at high temperatures

E

Q21

X-rays can be used in the study of crystal structures because they

A

have a very long-reaching wavelength

B

have an extremely short wavelength

C

are invisible

D

are very fast

E

Q22

The particle and wave nature of matter are demonstrated in the equation

A

λ = hc/E

B

λ =h/p

C

λ = c/f

D

λ = 2d sinθ

E

Q23

The binding energy of helium 4/2 He is

A

4.033 U

B

2.017 U

C

0.033 U

D

0.330 U

E

Q24

The difference between x-rays and gamma rays is that

A

x-rays are more penetrating than gamma rays

B

x-rays are electromagnetic radiations while gamma rays are negatively charged radiations

C

-rays have higher frequencies than gamma rays

D

x-rays arise from energy changes in the electronic structure of atoms while gamma rays come from the nucleus

E

Q25

In a semiconductor junction diode, as the depletion or barrier layer is forward-biased, the layer

A

narrows

B

remains constant

C

widens then narrows

D

widens

E

Q26

When a nucleus is formed by bringing protons and neutrons together, the actual mass of the formed nucleus is less than the sum of the masses of the constituent protons and neutrons. The energy equivalent of this mass difference is the

A

stability energy

B

lost energy

C

work function

D

binding energy

E

Q27

An electron makes a transition from a certain energy level E_{k }to the ground sate E^{o} . If the frequency of emission is 8.0 X 10^{14}Hz, the energy emitted is

A

5.28 x 10^{19} J

B

8.25 x 10^{19} J

C

5.28 x 10^{-19} J

D

8.25 x 10^{-19 }J

E

Q28

In a fission process, the decrease in mass is 0.01%. How much energy could be obtained from the fisssion of 1.0g of the material?

A

9.0 x 10^{10}J

B

6.3 x 10^{11}J

C

9.0 x 10^{11}J

D

9.0 x 10^{9}J

E

Q29

The major difference between a pure semiconductor and a pure metal is that

A

the resistance of metals increases with temperature, while for semiconductors, it is the reverse

B

metals are harder than semiconductors

C

metals have forbidden gaps while semiconductors have not

D

while the resistance of metals decrease with temperature, the reverse is the case for semiconductors

E

Q30

If the uncertainty in the measurement of the position of a particle is 5 X 10^{-10}m, the uncertainty in the momentum of the particle is

A

3.30 x 10^{-44} Ns

B

3.30 x 10^{-24} Ns

C

1.32 x 10^{-44} Ns

D

1.32 x 10^{-24} Ns

E

Q31

The maximum kinetic energy of the photoelectrons emitted from a metal surface is 0.34eV . If the work function of the metal surface is 1.83eV, find the stooping potential

A

1.09V

B

2.17V

C

0.34V

D

1.49V

E

Q32

The count rate of a radioactive material is 800 count/min. If the half-life of the material is 4 days, what would the count rate be 16 days later?

A

50 count/min

B

25count/min

C

200 count/min

D

100 count/min

E

Q33

The particle that is responsible for nuclear fission in a nuclear reactor is

A

electron

B

photon

C

neutron

D

proton

E

Q34

The energy associated with the photon of a radio transmission at 3 x 10^{5 }Hz is

A

1.30 X 10^{-29} J

B

2.00 x 10^{-29} J

C

1.30 x 10^{-28 }J

D

2.00 x 10^{-28} J

E

Q35

The percentage of the original nuclei of a sample of a radioactive substance left after 5 half-lives is

A

1%

B

8%

C

5%

D

3%

E

Q36

Pure silicon can be converted to a p-type material by adding a controlled amount of

A

pentavalent atoms

B

hexavalent atoms

C

tetravalent atoms

D

trivalent atoms

E

Q37

23 Na + X ---> 20 F + 4 He
11 9 2
What particle is X in the reaction above ?

A

Beta

B

Gamma

C

Alpha

D

Neutron

E

Q38

The ratio of electrostatic force FE to gravitational force FG between two protons each of charge e and mass m, at a distance d is

A

e^{2} / 4πe_{o} Gm^{2}

B

Gm^{2} / 4πe_{o}e^{2}

C

e / 4πe_{o} Gm

D

e^{2} / Gm^{2}

E

Q39

The particle emmited when 39/19 K decays to 39/19 K is

A

beta

B

alpha

C

gamma

D

electron

E

Q40

Which of the following metals will provide the greatest shield against ionizing radiation?

A

Aluminium

B

Iron

C

Lead

D

Manganese

E

Q41

The process of energy production in the sun is

A

nuclear fusion

B

nuclear fission

C

radioactive decay

D

electron collision

E

Q42

If the fraction of the atoms of a radioactive material left after 120 years is 1/64, what is the half-life of the material?

A

2 years

B

10 years

C

20 years

D

24 years

E

Q43

A certain radioactive source emits radiations that were found to be deflected by both magnetic and electric fields. The radiations are

A

x-rays

B

beta rays

C

gamma rays

D

ultra-violet rays

E

Q44

In a pure semiconductor, the number of electrons in the conduction band is

A

equal to the number of holes in the valence band

B

greater than the number of holes in the valence band

C

less than the number of holes in the valence band

D

twice the number of holes in the valence band

E

Q45

Light of energy 5 eV falls on a metal of work function 3 eV and electrons are liberated. The stopping potential is

A

15.0 V

B

8.0 V

C

2.0 V

D

1.7 V

E

Q46

If the frequency of an emitted x-rays is 1.6 x 10^{16}Hz, the accelerating potential is

A

6.6V

B

66.3 V

C

663.0 V

D

6630.0 V

E

Q47

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

E

Q48

What is the speed of particle of mass 10^{-27} kg whose wavelength is 10^{-8} m ?

A

6.63 ms^{-1}

B

66.30 ms^{-1}

C

663.00 ms^{-1}

D

6630.00 ms^{-1}

E

Q49

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 emmited alpha particles

D

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

E

Q50

23/11 Na + Proton ----> p/q + 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

E

Q51

A semi-conductor diode is used in rectifying alternating current into direct current mainly because it

A

allows current to flow in either direction

B

is non-linear

C

offers a high input resistance

D

allows current to flow only in one direction

E

Q52

In semi- conductors, the carriers of current at room temperature are

A

electrons only

B

electrons and holes

C

holes only

D

electrons and ions

E

Q53

If Δ x is the uncertainty in the measurement of the position of a particle along the x-axis and ΔPx is the uncertainity in the measurement of the linear momentum along the x-axis, then the uncertainty principle relation is given as

A

Δ x ΔPx ≥h

B

Δ x ΔPx = 0

C

Δ x ΔPx < h

D

Δ X ΔPx = infinity

E

Q54

A radioactive substances has a half-life of 80 days. If the initial number of atoms in the sample is 6.00 x 10^{10} , how many atoms would remain at the end of 320 days?

A

3.75 X 10^{9}

B

7.50 X 109

C

3.00 X 10^{10}

D

5.63 X 10^{10}

E

Q55

In a nuclear fusion experiment, the loss of mass amounts to 1.0 X 10^{-6} kg. The amount of energy obtained from the fussion is

A

3.0 X 10^{-4} J

B

3.0 X 10^{-1} J

C

9.0 x 10^{4} J

D

9.0 x 10^{10 }J

E

Q56

In photoelectric effect, electrons will leave the metal surface when illuminated by light of appropriate frequency if the photon energy is

A

greater than work function

B

less than the work function

C

equal to the work function

D

equal to the maximum kinetic energy of the electrons

E

Q57

One of the features of the fission process is that

A

its products are not radioactive

B

it leads to chain reaction

C

neutrons are not released

D

the sum of the masses of the reactants equals the sum of the masses of the products

E

Q58

The graphite rods surrounding the uranium fuel rods in a nuclear reactor, are used to

A

absorb the neutrons and hence halt the nuclear process

B

create the neutrons and hence start up the nuclear process

C

slow down the neutrons and hence slow the nuclear process

D

speed up the neutrons and hence speed up the nuclear process

E

Q59

The half-life of a radioactive element is 9 days. What fraction of atoms has decayed in 36 days?

A

1/16

B

1/4

C

1/2

D

15/16

E

Q60

A light of energy 5eV falls on a metal and the electrons with a maximum kinetic energy of 2eV are ejected . The work function of the metal is

A

0.4 eV

B

2.5 eV

C

3.0 eV

D

7.0 eV

E