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johnmulu answered the question on February 7, 2017 at 07:02
- In certain pinhole camera, the screen is 10cm from the pinhole. When the camera is placed 6 m away from a tree, a sharp image of the tree 16 cm high(Solved)
In certain pinhole camera, the screen is 10cm from the pinhole. When the camera is placed 6 m away from a tree, a sharp image of the tree 16 cm high is formed on the screen. Determine the height of the tree
Date posted: February 7, 2017. Answers (1)
- What is meant by virtual image?(Solved)
What is meant by virtual image?
Date posted: February 7, 2017. Answers (1)
- A vertical object placed on a bench is observed to have three shadows of different sharpness, in different directions(Solved)
A vertical object placed on a bench is observed to have three shadows of different sharpness, in different directions. Explain this observation
Date posted: February 7, 2017. Answers (1)
- What property of light is suggested by the formation of shadows?(Solved)
What property of light is suggested by the formation of shadows?
Date posted: February 7, 2017. Answers (1)
- The melting point of Oxygen is given as -281.3oC. Convert this temperature to Kelvin (K)(Solved)
The melting point of Oxygen is given as -281.3oC. Convert this temperature to Kelvin (K).
Date posted: February 6, 2017. Answers (1)
- In a vacuum flask the walls enclosing the vacuum are silvered on the inside. State the reason for this(Solved)
In a vacuum flask the walls enclosing the vacuum are silvered on the inside. State the reason for this
Date posted: February 6, 2017. Answers (1)
- An electric heater is placed at equal distances from two similar metal cans A and B filled with water at room temperature(Solved)
An electric heater is placed at equal distances from two similar metal cans A and B filled with water at room temperature. The outer surface of can A is shiny while that of can B is dull black. State with reasons which can will be at higher temperature after the heater is switched on for some time.
Date posted: February 6, 2017. Answers (1)
- A wooden bench and a metal bench are both left in the sun for a long time. Explain why the metal bench feels hotter to touch(Solved)
A wooden bench and a metal bench are both left in the sun for a long time. Explain why the metal bench feels hotter to touch.
Date posted: February 6, 2017. Answers (1)
- Give reason why heat transfer by radiation is faster than heat transfer by conduction(Solved)
Give reason why heat transfer by radiation is faster than heat transfer by conduction.
Date posted: February 6, 2017. Answers (1)
- State two variables that must be controlled in an experiment for comparing the thermal conductivities of different metal rods of the same diameter (Solved)
State two variables that must be controlled in an experiment for comparing the thermal conductivities of different metal rods of the same diameter.
Date posted: February 6, 2017. Answers (1)
- When a liquid is heated in a glass flask, its level at first falls then rises. Explain this observation(Solved)
When a liquid is heated in a glass flask, its level at first falls then rises. Explain this observation.
Date posted: February 6, 2017. Answers (1)
- Clinical thermometer has a constriction in the bore just above the bulb. State the use of this constriction (Solved)
Clinical thermometer has a constriction in the bore just above the bulb. State the use of this constriction.
Date posted: February 6, 2017. Answers (1)
- Why is water not a suitable liquid for use in a barometer?(Solved)
Give reason why water is not a suitable liquid for use in a barometer.
Date posted: February 6, 2017. Answers (1)
- Explain why a glass container with thick walls is more likely to crack than one with a thin wall when a very hot liquid is poured into it.(Solved)
Explain why a glass container with thick walls is more likely to crack than one with a thin wall when a very hot liquid is poured into it.
Date posted: February 6, 2017. Answers (1)
- Give a reason why a concrete beam reinforced with steel does not crack when subjected to changes in temperature(Solved)
Give a reason why a concrete beam reinforced with steel does not crack when subjected to changes in temperature.
Date posted: February 6, 2017. Answers (1)
- One property of a liquid that is considered while constructing a liquid-in-glass thermometer is that the liquid expands more than the glass for the same temperature change(Solved)
One property of a liquid that is considered while constructing a liquid-in-glass thermometer is that the liquid expands more than the glass for the same temperature change. State any other two properties of the liquids that are considered.
Date posted: February 6, 2017. Answers (1)
- State why it is easier to separate water into drops than to separate a solid into smaller pieces(Solved)
State why it is easier to separate water into drops than to separate a solid into smaller pieces
Date posted: February 6, 2017. Answers (1)
- In a smoke cell experiment to demonstrate Brownian motion, smoke particles are seen moving randomly. State the cause of the randomness(Solved)
In a smoke cell experiment to demonstrate Brownian motion, smoke particles are seen moving randomly. State the cause of the randomness
Date posted: February 6, 2017. Answers (1)
- A drop of blue ink is introduced at the bottom of a beaker containing water. It is observed that after sometime, all water in the beaker turns blue(Solved)
A drop of blue ink is introduced at the bottom of a beaker containing water. It is observed that after sometime, all water in the beaker turns blue. Name the process that takes place.
Date posted: February 6, 2017. Answers (1)
- A bottle containing a smelling gas is opened at the front bench of a classroom. State the reason why the gas is detected throughout the room (Solved)
A bottle containing a smelling gas is opened at the front bench of a classroom. State the reason why the gas is detected throughout the room.
Date posted: February 6, 2017. Answers (1)