Two identical empty metal containers P and Q are placed over identical Bunsen burners and the burners lit. P is dull black while Q is shiny bright. After each container attains a temperature of #100^0C# the burners are turned off. Two identical test tubes containing water are suspended in each container without touching the sides as shown in figure 3.

Explain why the water in test tube in P becomes hot faster than Q.

Answer:

- Dull surfaces are good absorbers of heat. Container P therefore gives more heat

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The control grids in a Cathode Ray Oscilloscope (CRO) is used to control the brightness of the beam on the screen. How is this achieved? (Answered)
The control grids in a Cathode Ray Oscilloscope (CRO) is used to control the brightness of the beam on the screen. How is this achieved? .
Posted On:Thu 18, March 2021 04:11:37 am

State two differences between the cathode ray tube (CRT) of a T.V and the cathode ray oscilloscope (CRO). (Answered)
State two differences between the cathode ray tube (CRT) of a T.V and the cathode ray oscilloscope (CRO). .
Posted On:Thu 18, March 2021 04:15:27 am

Figure 3 shows the main features of a cathode ray tube (CRT) of a cathode ray oscilloscope (CRO). (i) Describe how the electrons are produced in the tube. (ii) State and explain the function of the grid. (iii) State what would be observed on the screen if an a.c voltage is connected across the y-plates. (iv) State how the deflection system of a television differs from that of a CRO. (Answered)
Figure 3 shows the main features of a cathode ray tube (CRT) of a cathode ray oscilloscope (CRO). (i) Describe how the electrons are produced in the tube. (ii) State and explain the function of the grid. (iii) State what would be observed on the screen if an a.c voltage is connected across the y-plates. (iv) State how the deflection system of a television differs from that of a CRO. .
Posted On:Thu 18, March 2021 04:24:25 am

Figure 6 shows a tube for investigating the properties of a beam of electrons. Use the information in the figure to answer question 8. What property of the beam of electrons shows that the electrons are travelling at a very high speed? (Answered)
Figure 6 shows a tube for investigating the properties of a beam of electrons. Use the information in the figure to answer question 8. What property of the beam of electrons shows that the electrons are travelling at a very high speed? .
Posted On:Thu 18, March 2021 04:28:25 am

(a) Figure 14 shows the features of a cathode ray tube. (i) Name the parts labeled A and B. (ii) Explain how the electrons are produced in the tube. (iii) State two functions of the anodes. (iv) At what part of the cathode ray tube would the time be connected? (v) Why is a vacuum created in the tube? (Answered)
(a) Figure 14 shows the features of a cathode ray tube. (i) Name the parts labeled A and B. (ii) Explain how the electrons are produced in the tube. (iii) State two functions of the anodes. (iv) At what part of the cathode ray tube would the time be connected? (v) Why is a vacuum created in the tube? .
Posted On:Thu 18, March 2021 04:36:33 am

Figure 14 (a) is a diagram of a cathode ray tube. M and N are parallel vertical plates (a) When switch S is open, a spot is seen at the centre of the screen as shown in figure 14(b). (i) State what happens to the sport when S is closed. (ii) State what would happen to the spot if the potential difference across MN is increased. (iii) State what would be seen on the screen if the battery is replace (Answered)
Figure 14 (a) is a diagram of a cathode ray tube. M and N are parallel vertical plates (a) When switch S is open, a spot is seen at the centre of the screen as shown in figure 14(b). (i) State what happens to the sport when S is closed. (ii) State what would happen to the spot if the potential difference across MN is increased. (iii) State what would be seen on the screen if the battery is replace .
Posted On:Thu 18, March 2021 04:49:22 am

State two differences between cathode rays and electromagnetic radiations. (Answered)
State two differences between cathode rays and electromagnetic radiations. .
Posted On:Thu 18, March 2021 04:51:08 am

Explain how electrons are produced in the Cathode ray tube. (Answered)
Explain how electrons are produced in the Cathode ray tube. .
Posted On:Thu 18, March 2021 04:52:24 am

The current of electrons hitting the screen of a cathode ray oscilloscope is 2.0 X #10^-4#A. Determine the number of electrons that strike the screen each second. (Take charge of an electron as 1.6 X#10^-19#C). (Answered)
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Posted On:Thu 18, March 2021 04:57:56 am

State and explain the function of the Grid in the cathode ray tube. (Answered)
State and explain the function of the Grid in the cathode ray tube. .
Posted On:Thu 18, March 2021 05:00:43 am

A trolley is moving at constant speed in friction compensated track. Some plasticine is dropped on the trolley and sticks on it. State with a reason what is observed about the motion of the trolley. (Answered)
A trolley is moving at constant speed in friction compensated track. Some plasticine is dropped on the trolley and sticks on it. State with a reason what is observed about the motion of the trolley. .
Posted On:Thu 18, March 2021 05:06:40 am

A gun is fired vertically upwards from the top of an open truck moving horizontally at a uniform velocity of #50 ms^-1#. The bullet achieves a maximum height of 45m. (i) State with reason whether or not the bullet will land on the truck. (ii) Calculate the distance covered by the truck just before the bullet reaches the level from which it was fired. (Use g=10 #ms^-2#). (Answered)
A gun is fired vertically upwards from the top of an open truck moving horizontally at a uniform velocity of #50 ms^-1#. The bullet achieves a maximum height of 45m. (i) State with reason whether or not the bullet will land on the truck. (ii) Calculate the distance covered by the truck just before the bullet reaches the level from which it was fired. (Use g=10 #ms^-2#). .
Posted On:Thu 18, March 2021 05:16:12 am

An industrial trolley of mass 20kg carrying a mass of 50kg is acted on by a constant force. The trolley moves along a horizontal smooth surface with an acceleration of 0.5 #ms^-2#. Determine the acceleration of the trolley after the mass falls off. (Answered)
An industrial trolley of mass 20kg carrying a mass of 50kg is acted on by a constant force. The trolley moves along a horizontal smooth surface with an acceleration of 0.5 #ms^-2#. Determine the acceleration of the trolley after the mass falls off. .
Posted On:Thu 18, March 2021 05:20:09 am

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Two identical spherical steel balls are released from the top of two tall jars containing liquids L1 and L2 respectively. Figure 3 shows the velocity – time graph of the motion of the balls. Explain the nature of the curves and state why they are different .
Posted On:Thu 18, March 2021 05:29:21 am

A train of mass 200 tonnes starts from rest and accelerates uniformly at 0.5 #ms^-2#. Determine its momentum after moving 100m (Answered)
A train of mass 200 tonnes starts from rest and accelerates uniformly at 0.5 #ms^-2#. Determine its momentum after moving 100m .
Posted On:Thu 18, March 2021 05:36:51 am

A high jumper usually lands on thick soft mattress. Explain how the mattress helps in reducing the force of impact. (Answered)
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Posted On:Thu 18, March 2021 05:39:22 am

A body resting on a horizontal surface is given an initial velocity V so that it slides on the surface for some distance before coming to a stop. Table 1 shows the distance d moved by the body of various values of V. Given that #V^2# = 20μd where μ is a constant for the surface, plot an appropriate graph and use it to determine μ. (Answered)
A body resting on a horizontal surface is given an initial velocity V so that it slides on the surface for some distance before coming to a stop. Table 1 shows the distance d moved by the body of various values of V. Given that #V^2# = 20μd where μ is a constant for the surface, plot an appropriate graph and use it to determine μ. .
Posted On:Thu 18, March 2021 05:49:17 am

A resultant force F acts on a body of mass m causing an acceleration #a1# on the body. When the same force acts on a body of mass 2m, it causes an acceleration #a_2#. Express #a_2# in terms of #a_1# (Answered)
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Posted On:Thu 18, March 2021 05:55:50 am

A trolley is moving at a uniform speed along a track. A piece of plasticine is dropped on the trolley and sticks on it. Explain why the trolley slows down. (Answered)
A trolley is moving at a uniform speed along a track. A piece of plasticine is dropped on the trolley and sticks on it. Explain why the trolley slows down. .
Posted On:Thu 18, March 2021 05:57:16 am

A footballer kicks a ball of mass 0.6 kg initially at rest using a force of 720N. if the foot was in contact with the ball for 0.1 seconds, what was the takeoff speed of the ball? (Answered)
A footballer kicks a ball of mass 0.6 kg initially at rest using a force of 720N. if the foot was in contact with the ball for 0.1 seconds, what was the takeoff speed of the ball? .
Posted On:Thu 18, March 2021 06:00:43 am

A car of mass 800kg starts from rest and accelerates at 1.2 #ms^-2#. Determine its momentum after it has moved 400m from the starting point (Answered)
A car of mass 800kg starts from rest and accelerates at 1.2 #ms^-2#. Determine its momentum after it has moved 400m from the starting point .
Posted On:Thu 18, March 2021 06:09:32 am

A cart of mass 30kg is pushed along a horizontal path by a horizontal force of 8N and moves with a constant velocity. The force is then increased to 14N. Determine: (a) The resistance to the motion of the cart (b) The acceleration of th cart. (Answered)
A cart of mass 30kg is pushed along a horizontal path by a horizontal force of 8N and moves with a constant velocity. The force is then increased to 14N. Determine: (a) The resistance to the motion of the cart (b) The acceleration of th cart. .
Posted On:Thu 18, March 2021 06:13:57 am

Figure 5 is a graph of net force on a body against its velocity as it falls through a liquid. Determine the terminal velocity of the body (Answered)
Figure 5 is a graph of net force on a body against its velocity as it falls through a liquid. Determine the terminal velocity of the body .
Posted On:Thu 18, March 2021 06:17:19 am

Figure 12 shows a lorry towing a trailer using a rope. The lorry exerts a force N on the trailer and the trailer exerts an equal but opposite force M on the lorry. The frictional force between the trailer and the road is F. Explain how the forces N, M and F enable the trailer to move. (Answered)
Figure 12 shows a lorry towing a trailer using a rope. The lorry exerts a force N on the trailer and the trailer exerts an equal but opposite force M on the lorry. The frictional force between the trailer and the road is F. Explain how the forces N, M and F enable the trailer to move. .
Posted On:Thu 18, March 2021 06:21:36 am

Figure 13 shows a frictionless trolley of mass 2kg moving with uniform velocity towards a wall. At the front of the trolley is a spring whose spring constant is 25 Nm-1. The trolley comes to rest momentarily after compressing the spring by 3cm and the rebounds from the wall. (i) Determine: (I) The force exerted on the wall by the spring. (II) The maximum acceleration of the as it rebounds from the (Answered)
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Posted On:Thu 18, March 2021 06:31:01 am

A student pulls a block of the wood along a horizontal surface by applying a constant force. State the reason why the block moves at a constant velocity. (Answered)
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Posted On:Thu 18, March 2021 06:34:06 am

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Posted On:Thu 18, March 2021 06:35:43 am