# Key points in jamb physics

#### Key Points on Jamb Physics hot topics (1 to 10)

1) The classification of Wave are:

• Mechanical Wave (E.g Water and Sound Wave)
• Electromagnetic Wave (E.g Gamma and X-Rays)
• Progressive/Travelling Wave (Water And Sound)
• Stationary/Standing Wave (Nodes And Antinodes)
• Longitudinal Wave (E.g Sound Waves)
• Transverse Wave (E.g Waves in Pipe and Strings).

2) Stationary Wave occur when two interfering waves of the same amplitude and frequency travel in opposite direction.

3) Velocity of Sound In:

• Air is 332m/s
• Water (Liquid) is 1435m/s
• Iron (Solid) is 5000m/s

4) The velocity of Echo is equal to the total distance traveled by the sound divided by the time taken.

5) The quality of sound depends on the number of overtones or harmonics. It makes it possible to distinguish between two instruments playing the same note.

6) Vibration can either be free, forced or resonance.

7) Eclipse occurs due to the travel of light in a straight line.

8) The application of plane mirrors are Periscope, Kaleidoscope and Sextant.

9) Refraction occurs at constant frequency.

10) Hydrogen spectrum has all colors of white light, Sodium vapour has yellow line (spectrum) and Mercury vapour has Blue and Green spectrum.

#### Hot Points And Topics In Jamb Physics (10 to 20)

11) Another word for electrolysis is the chemical effect of current.

12) Passage of current through liquid doesn’t obey Ohms law.

13) Magnetic fields are oval in shape.

14) Angle of dip is 90 degree at the magnetic poles and zero at the equator.

15) The strength of Magnet is greatest at the pole.

16) All electric charges are multiples of the charges of an electron.

17) Factors affecting capacitance are: Area of plates, distance between the plates and dielectrics between the plates.

18) Examples of dielectric materials are Paraffin wax, Polythene, Ebonite and Glass.

19) Sliding friction are less than limiting friction.

20) EMF is the algebraic sum of potential difference acting in a circuit.

#### Hot Topics in Jamb Physics (20 to 30)

21) Electromagnetism is the production of current from Magnet.

22) In a closed circuit, the induced EMF gives rise to induced current.

23) Eddy current is used in damping moving coil, speedometers and induction coil.

24) Transformer steps up or steps down voltage at the same frequency.

25) The Inductor finds application in choke making industry.

26) Choke is used for varying current.

27) The induced voltage is equal to the rate of change of magnetic flux.

28) Solar cells convert sunlight energy directly into electrical energy.

29) Local action is caused by impurity of zinc plate.

30) Eddy current is reduced by lamination.

#### Hot Key Points In Jamb UTME Physics (30 to 40)

31) Induction coil is used to step up voltage in DC circuit.

32) Generator operates based on the principle of self induction.

33) DC doesn’t oscillate and as such does not have a frequency.

34) Telephone receiver or earpiece works on the principle of magnetic effect of current.

35) Plane mirrors do not enlarge or reduce the size of object. Object size is the same as image size.

36) Factors affecting resistance are:

• Length of conductor.
• Area of conductor.
• Temperature and
• Type of material used.

37) Triangular prism with two convex lenses is used to produce pure spectrum.

38) If light energy is less than the work function, no electron will be emitted and vice versa.

39) Work function is the energy that can produce threshold frequency (W=hf).

40) The uncertainty principle only works for atoms and not irons.

#### Likely Jamb physics questions to Note (40 to 50)

41) The applications of total internal reflection are Mirage and Fish view under water.

42) Binding energy is the reason for mass defect.

43) Bismuth is diamagnetic.

44) Current is the rate of flow of charge.

45) Kirchoff’s current law states that the algebraic sum of currents flowing into the circuit is equal to the algebraic sum of currents leaving the circuit.

46) Kirchoff’s voltage law states that the sum of all the voltages around circuit loop is equal to zero.

47) Example of refrigerants are Ammonia and Ethyl Chloride.

48) Kaleidoscope is designed to obtain different color patterns.

49) To convert a Galvanometer to Ammeter, a low resistance called shunt is connected in parallel with the meter.

50) As temperature increases, the speed of sound increases.

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