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# IJMB Physics 102 Past Questions 2022

IJMB Physics 102 Past Questions 2022 for students who are currently preparing for their IJMB examination, interested students are advised to study these past questions diligently and share them with their friends for group reading.

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INTERIM JOINT MATRICULATION BOARD EXAMINATION 2022.

SUBJECT: PHYSICS PAPER-II

SCHEDULED: THURSDAY 23RD  JUNE, 2022

TIME ALLOWED: THREE HOURS (3 HRS)

INSTRUCTIONS:

I. Answer All questions in Section A and ONE (1) question from each section B and D and TWO (2) questions from Section C.

II. Only a scientific calculator can be used.

Useful constant:

Charge on the electron e = -1.6 x 10-19C

Electron volt eV = 1.6 x 10-19J

Mass of electron Me = 9.0 x 10-31Kg

Permeability of free space 0 = 4π x 10-7NA-2

Permittivity of free space 0 = 8.85 x 10-12Fm-1

Electrical constant of proportionality 14πrϴ = 9 x 109Nm2C-2

Plank’s constant h = 6.6 x 10-34Js

Velocity of light in free space c = 3.0 x 108ms-1

Avogadro’s number NA = 6 x 1023mol-1

Atomic mass unit 1u = 931MeV

Universal gravitational constant G = 6.67 x 10-11Nm2Kg-2

SECTION A

Answer all the questions from this sections (40 marks)

1. When light travelling in the air, enters a glass slab. Explain how its: velocity, frequency, wavelength and intensity behaved before and after it enters the slab, (ray diagram not needed).

2. If a ray of light incidents on a glass block of refractive index 32, calculate the angle of incidence of the ray of light if the angle between the reflected and refracted rays is 900?

3. Briefly explain the effects of increasing temperature in conductors, semiconductors and insulators.

4. Calculate the radius of a piece of copper wire 40m having a resistance of 0.25, assuming the resistivity of copper as 2.0 x 10-8Ωm.

5. A cell supplies 0.5A of current which is connected across an external resistor of resistance 12 Ω and is current of 0.23A when connected across an external resistor of resistance 23 Ω.  Determine the emf and internal resistance of the cell.

6. Two resistors are connected in series across a 24V supply and a current of 6A flows in the circuit. If one of the resistors has a resistance of 20 Ω, determine the value of the other resistor and the p.d across the 20 resistors.

7. Consider a certain capacitor of cross-sectional area 4cm2 separated by 0.1mm of silk material of relative permittivity 100. (i)  Calculate the capacitance of the capacitor. (ii)  When this capacitor is charged, find the p.d between the plates?

8. The photoelectric threshold wavelength of a mental is 3800A. When UV light of wavelength 4600A is incident o the metal surface. Calculate the value of its work function in eV.

9. The Hb line of the Balmer series corresponds to the transition from n = 4 to n = 2 level. Calculate the wavelength and the frequency of the Hb line of the Balmer series for hydrogen. (Rydberg constant is 1.097 x 107ms-1).

10. What type of extrinsic semiconductor would be formed when:

(i)   Germanium is doped with indium (indium is trivalent)?

(ii)  Silicon is doped with bismuth?

SECTION B   GEOMETRICS OPTICS (20 marks)

Attempt one (1) question only from this section

11a. Use a ray diagram to explain the following terms as applied to spherical mirrors (concave and convex); centre of curvature, pole, principal axis, principal focus, the radius of curvature and aperture when a narrow beam of light parallel and near the principal axis is incident on the mirror.

11b. Assume that a very thick needle is placed at a distance of 30cm from a concave mirror of a focal length of 20cm, and determine the image distance and its magnification. Also, draw the ray diagram.

11c. If the speed of light in a vacuum is 3 x 108ms-1, calculate the speed of light in a medium whose critical angle is 450.

12a. (i) Explain in detail the following terms; reflection and refraction of light waves. Use ray diagrams where necessary to support your answer.

(ii) Sketch ray diagrams refraction of light waves under the following special conditions at normal incidence (00) for two different media and refraction at any incident angle when both media are the same.

12b. If a ray of monochromatic light passes through an equilateral glass prism of refractive index 1.62 when the angle of incidence is the same as the angle of emergence. Find the angle of deviation at an incident angle 370. What would be the angle of minimum deviation of this glass?

12c. Given two thin lenses of power +6D and -2D are in contact with each other. Calculate the focal length of the combination.