X-rays are produced when very fast moving electrons are suddenly stopped by a heavy material whereas ultra-violet rays come from very hot bodies.
Alambi answered the question on February 17, 2019 at 10:45
- State two safety precautions that should be observed when using electrical hand tools. (Solved)
State two safety precautions that should be observed when using electrical hand tools.
Date posted: February 13, 2019. Answers (1)
- A fishing boat is at rest on sea water with a steel anchor over the side. Explain what would happen to the volume of displaced...(Solved)
A fishing boat is at rest on sea water with a steel anchor over the side. Explain what would happen to the volume of displaced water by the boat when:
a) the anchor is lowered and left hanging in water
b) the anchor rests on the bed at the sea.
Date posted: February 13, 2019. Answers (1)
- A transformer of 480 turns in the primary coil is used to connect a 9V a.c electric device to a 240V a.c mains supply. Calculate...(Solved)
A transformer of 480 turns in the primary coil is used to connect a 9V a.c electric device to a 240V a.c mains supply. Calculate the number of turns in the secondary coil.
Date posted: February 12, 2019. Answers (1)
- A transformer in a welding machine supplies 6V from a 240V mains supply. If the current used in the welding is 30A. Determine the current...(Solved)
A transformer in a welding machine supplies 6V from a 240V mains supply. If the current used in the welding is 30A. Determine the current in the mains.
Date posted: February 12, 2019. Answers (1)
- A body weighs 32N in kerosene and 30N in water. If the body weighs 40N in air, find the relative density of kerosene.(Solved)
A body weighs 32N in kerosene and 30N in water. If the body weighs 40N in air, find the relative density of kerosene.
Date posted: February 11, 2019. Answers (1)
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Define angular displacement and state its unit.
Date posted: February 10, 2019. Answers (1)
- A cube of 3cm3 weighs 18.7N in air. Calculate:
a) The density of the material making the cube.
b) The apparent weight when completely immersed in...(Solved)
A cube of 3cm3 weighs 18.7N in air. Calculate:
a) the density of the material making the cube
b) the apparent weight when completely immersed in a liquid of density 0.8g/cm3.
Date posted: February 7, 2019. Answers (1)
- A certain transformer steps down mains supply from 240V to 6C. There are 1200 turns in the primary circuit. A bulb of 36W is connected...(Solved)
A certain transformer steps down mains supply from 240V to 6V. There are 1200 turns in the primary circuit. A bulb of 36W is connected to the secondary circuit. Given that the efficiency of the transformer is 100% determine:
a) The number of turns in the secondary circuit.
b) The current in the primary circuit.
Date posted: February 6, 2019. Answers (1)
- A metal block of density 7.8g/cm3 weighs 117N in air. Find the weight of the block when fully immersed in water of density 1.0g/cm3.(Solved)
A metal block of density 7.8g/cm3 weighs 117N in air. Find the weight of the block when fully immersed in water of density 1.0g/cm3.
Date posted: February 2, 2019. Answers (1)
- a) An object of mass 0.60kg tied to the end of a rope is whirled in a horizontal circle of radius 2.0m with a constant...(Solved)
a) An object of mass 0.60kg tied to the end of a rope is whirled in a horizontal circle of radius 2.0m with a constant speed of 10m/s. Find the tension in the string.
Date posted: February 1, 2019. Answers (1)
- What do you understand by the term angular velocity?
Deduce the relationship between the linear speed and angular velocity.(Solved)
What do you understand by the term angular velocity?
Deduce the relationship between the linear speed and angular velocity.
Date posted: January 31, 2019. Answers (1)
- An object floats in sea water of density 1.03x10^3kg/m^3. It displaces 260m^3 of sea water. Find the mass of the object.(Solved)
An object floats in sea water of density 1.03x10^3kg/m^3. It displaces 260m^3 of sea water. Find the mass of the object.
Date posted: January 30, 2019. Answers (1)
- A sling of length 1m and holding a stone of mass 200g at its free end is whirled in a horizontal plane such that it...(Solved)
A sling of length 1m and holding a stone of mass 200g at its free end is whirled in a horizontal plane such that it completes 10 revolutions in 5 seconds. Determine:
a) Tension in the sling
b) The frequency of rotation
c) The velocity with which the stone clips off when released
Date posted: January 30, 2019. Answers (1)
- A particle revolves at 2Hz in a circle of radius 2m. Calculate its linear speed and angular velocity.(Solved)
A particle revolves at 2Hz in a circle of radius 2m. Calculate its:
a) Linear speed
b) Angular velocity
Date posted: January 29, 2019. Answers (1)
- A bucket of water containing water is rotated in a vertical circle of radius 80cm. What should its velocity be so that the water may...(Solved)
A bucket containing water is rotated in a vertical circle of radius 80cm. What should its velocity be so that the water may not spill out?
Date posted: January 28, 2019. Answers (1)
- Explain why an object Weighs more in air than when fully immersed in water.(Solved)
Explain why an object Weighs more in air than when fully immersed in water.
Date posted: January 21, 2019. Answers (1)
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A spring supporting a weight of 30N extends by 1.5 cm. Determine the spring constant.
Date posted: January 21, 2019. Answers (1)
- A uniform plank of wood of length 5 m is pivoted at its centre. A girl of mass 32 kg sits at one end of...(Solved)
A uniform plank of wood of length 5 m is pivoted at its centre. A girl of mass 32 kg sits at one end of the plank. Determine how far from the pivot a boy of mass 40 kg should sit in order to balance the plank.
Date posted: January 21, 2019. Answers (1)
- A screen is placed 80cm from an object. A lens is used to produce on the screen an image with a magnification of 3. What...(Solved)
A screen is placed 80cm from an object. A lens is used to produce on the screen an image with a magnification of 3. What is the distance between the object and the lens? Calculate the focal length of that lens.
Date posted: January 21, 2019. Answers (1)
- A bullet is shot vertically upward and rises for a maximum height of 1000 m. What is the initial velocity...(Solved)
A bullet is shot vertically upward and rises for a maximum height of 1000m. What is the initial velocity of the bullet and the total time of flight?
Date posted: January 14, 2019. Answers (1)