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At night, the mages of air close to the ground are cooler than those higher above. Sound
get refracted towards the earth.
sharon kalunda answered the question on April 4, 2019 at 13:20
- A boy standing in front of a cliff blows a whistle and hears the echo after 0.5 seconds. He then
moves 17m further away form the...(Solved)
A boy standing in front of a cliff blows a whistle and hears the echo after 0.5 seconds. He then
moves 17m further away form the cliff and blows the whistle again. He now hears the echo after
0.6seconds. Determine the speed of the sound
Date posted: April 4, 2019. Answers (1)
- A girl standing 220m from the foot of a high wall claps her hands and the echo reaches her
1.29 seconds later. Calculate the velocity of...(Solved)
A girl standing 220m from the foot of a high wall claps her hands and the echo reaches her
1.29 seconds later. Calculate the velocity of sound in air using this observation
Date posted: April 4, 2019. Answers (1)
- The human ear can distinguish two sounds as separate only if they need it at least 0.1 seconds
apart. How far from a wall must an...(Solved)
The human ear can distinguish two sounds as separate only if they need it at least 0.1 seconds
apart. How far from a wall must an observer be in order to hear an echo when he shouts.
(Speed of sound = 330m/s)
Date posted: April 4, 2019. Answers (1)
- Figure below shows a ray of light traveling from glass to water.(Solved)
Figure below shows a ray of light traveling from glass to water.
Calculate the angle of incidence if the refractive index of glass and water are 3/2 and 4/3 respectively
Date posted: April 4, 2019. Answers (1)
- The figure below represents a ray of light falling normally on the curved surface of a
semi- circular glass block A at an angle of 32°...(Solved)
The figure below represents a ray of light falling normally on the curved surface of a
semi- circular glass block A at an angle of 32° at O and emerging into air at an angle of 48°
Calculate the absolute refractive index of the glass of which the block is made.
(Assume air is a vacuum)
Date posted: April 4, 2019. Answers (1)
- The refractive index of paraffin is 1.47 and that of glass is 1.55. Determine the critical
angle of a ray of light travelling from glass to...(Solved)
The refractive index of paraffin is 1.47 and that of glass is 1.55. Determine the critical
angle of a ray of light travelling from glass to paraffin
Date posted: April 4, 2019. Answers (1)
- The following figure shows an electric circuit in which five resistors are connected
to a battery of e.m.f 4.0V and negligible internal resistance.(Solved)
The following figure shows an electric circuit in which five resistors are connected
to a battery of e.m.f 4.0V and negligible internal resistance.
Determine:
(i) The total resistance of the circuit
(ii) The potential difference between Y and Q
Date posted: April 4, 2019. Answers (1)
- In the circuit diagram below, X is a fixed resistor while Y can be varied between O
and 100ohms using a sliding jockey(Solved)
In the circuit diagram below, X is a fixed resistor while Y can be varied between O
and 100ohms using a sliding jockey
Calculate:
(i) The minimum possible current in the circuit
(ii) The maximum possible current in the circuit
Date posted: April 4, 2019. Answers (1)
- Four capacitors of capacitance, 3µf, 4µf, 5µf and 3µf are arranged as shown below. Find the total capacitance.(Solved)
Four capacitors of capacitance, 3μf, 4μf, 5μf and 3μf are arranged as shown below. Find the capacitance.
Date posted: April 4, 2019. Answers (1)
- In an experiment to determine the resistance of a nichrome wire using the metre bridge, the
balance point was found to be at 38cm mark. If...(Solved)
In an experiment to determine the resistance of a nichrome wire using the metre bridge, the
balance point was found to be at 38cm mark. If the value of the resistance in the right hand
gap needed to balance the bridge was 25ohms, Calculate the value of resistance of nichrome wire
Date posted: April 4, 2019. Answers (1)
- The diagram in the figure below shows a wheat stone bridge(Solved)
The diagram in the figure below shows a wheat stone bridge
K, L, M and N are four resistors joined as shown. The value of resistance of resistor K is
unknown. I1, I2, I3 and I4 are the amount of current passing through K, M, L and N respectively.
It is also provided that L is a variable resistor.
(i) Explain how the set-up is used to determine the value of unknown resistance of K
(ii) State why wheat stone bridge is more accurate in measuring resistance than the voltmeter-ammeter
method
Date posted: April 4, 2019. Answers (1)
- A transformer is designated to work from a 240V a.c. mains and to give a supply of 8V
to ring house bells. The primary has 4800...(Solved)
A transformer is designated to work from a 240V a.c. mains and to give a supply of 8V
to ring house bells. The primary has 4800 turns.
(i) What type of transformer is this? Give a reason.
(ii) Why is the iron core laminated?
(iii) Calculate the secondary turns if the efficiency is 100%.
Date posted: April 4, 2019. Answers (1)
- Study the circuit diagram shown below.(Solved)
Study the circuit diagram shown below.
(i) Determine the reading of the voltmeter V.
(ii) Determine the reading of the ammeter A.
(iii) Explain the effect on the reading of the voltmeter if the 3ohms resistor is altered to be 6ohms
Date posted: April 4, 2019. Answers (1)
- In the configuration of resistors given below, determine the current through the 5ohms resistor.(Solved)
In the configuration of resistors given below, determine the current through the 5ohms resistor.
Date posted: April 4, 2019. Answers (1)
- The ammeter in the circuit below has negligible internal resistance. The cell has internal
resistance of 0.5? and an electromotive force of 3.0V(Solved)
The ammeter in the circuit below has negligible internal resistance. The cell has internal
resistance of 0.5ohms and an electromotive force of 3.0V
Determine the value of current the ammeter registers when switch S is closed
Date posted: April 4, 2019. Answers (1)
- In figure the voltmeter reads 2.1V when the switch is closed, the voltmeter reads 1.8v and
the ammeter 0.1 A(Solved)
In figure the voltmeter reads 2.1V when the switch is closed, the voltmeter reads 1.8v and
the ammeter 0.1 A
Determine:
i) The e.m.f of the cell
ii) The internal resistance of the cell
iii) The resistance of the of the lamp
Date posted: April 4, 2019. Answers (1)
- Three resistors of resistance 2.0ohms and 6.0ohms are connected together in a circuit. Draw
a circuit diagram to show the arrangement of the resistors which gives(Solved)
Three resistors of resistance 2.0ohms and 6.0ohms are connected together in a circuit. Draw
a circuit diagram to show the arrangement of the resistors which gives
i) Effective resistance of 3.0ohms
ii) Minimum resistance
Date posted: April 4, 2019. Answers (1)
- The ammeter in the figure below shows a reading of 2A. What is the reading of the
voltmeter v.?(Solved)
The ammeter in the figure below shows a reading of 2A. What is the reading of the
voltmeter v.?
Date posted: April 4, 2019. Answers (1)
- A lady uses a ramp to lift 1500N load though a vertical distance of 10m. The ramp makes an
angle 30o to the horizontal. If the...(Solved)
A lady uses a ramp to lift 1500N load though a vertical distance of 10m. The ramp makes an
angle 30o to the horizontal. If the efficiency of the ramp is 75%:
(i) Calculate the V.R of the machine
(ii) Find the mechanical advantage
iii) Find the effort needed to move the load up the ramp at constant velocity
Date posted: April 4, 2019. Answers (1)
- A car starting from rest accelerated uniformly for 5minutes to reach 30m/s. it continues at this speed for the next 20minutes and then decelerates uniformly...(Solved)
A car starting from rest accelerated uniformly for 5minutes to reach 30m/s. it continues at this speed for the next 20minutes and then decelerates uniformly to come to a stop in 10minutes. On the axes provided, sketch the graph of the velocity against time for the motion of the car.
Date posted: April 4, 2019. Answers (1)