An atom with 5 free electrons is said to be ?
- trivalent
- covalent
- pentavalet
Oxygen has a valency of ?
- 6
- 2
- 8
An isotope of an element will have more/less _________ than usual?
- protons
- neutrons
- electrons
Which of the following is an example of a Longitudinal Wave ?
- Sound Wave
- Radio Wave
- Light Wave
Which has the most effect on the speed of sound in air?
- Frequency
- Wavelength
- Temperature
In which medium does sound travel the fastest?
- Air
- Steel
- Water
Wavelength is ?
- distance between top and bottom
- distance between crests
- distance from trough to crest
The speed of sound in dry air is 331 m/s. In a solid the speed would ?
- decrease
- increase
- stay the same
Intensity of sound waves?
- vary directly as per distance from source
- is not affected by distance
- varies inversely as the square of distance from source
Quality of sound is dependant on ?
- number and pitch of harmonics
- medium it is traveling through
- frequency of the supply
The first overtone of a sound wave is the ?
- 2nd harmonic
- fundamental frequency
- 1st harmonic
Particles vibrating in air?
- tend to give off heat
- produce waves
- tend to give off light
The speed of sound in air at 0 °C is approximately ?
- 181 m/s
- 3 * 108 m/s
- 331 m/s
A Concave mirror is used in ?
- a rear view mirror
- a periscope
- headlights
The light gathering power of a lens is indicated by its ?
- thickness of the lens
- focal ratio
- material
The amount of light emitted by a lamp can be measured in ?
- luxors
- lumens
- candle's
A passive sensor ?
- requires power for the transmitter
- requires power for the sensor
- does not require power
When an emergent light wave enters a divergent lens?
- it is s spherical
- it will focus behind the lens
- it will focus beyond the lens
The fibre optic receiver is a ?
- light emitting diode
- laser diode
- photodiode
A material, which has a varying refractive index is a ?
- single index
- step index
- double index
How far will light travel in one year ?
- 9.46 * 1015 m
- 1.5 * 1011 m
- 3 * 1015 m
Regenerators are used in fibre optic systems to reduce ?
- dispersion
- random emission
- attenuation
Heat transmission by convection is confined to?
- gases and solids
- liquids and gases
- solids and liquids
The Steam Point of water is ?
- 373 Kelvin
- 0 Kelvin
- 273 Kelvin
Combined gas law relates volume, pressure and?
- velocity
- density
- temperature
What is meant by adiabatic ?
- Some heat crosses the boundary
- No heat crosses the boundary
- All heat crosses the boundary
A process where heat is given off to its surroundings is calle ?
- isothermal
- adiabatic
- isobaric
A compressor increases ?
- moving energy
- kinetic energy
- potential energy
A process where pressure does not change is known as?
- isobaric
- isothermic
- isochoric
A process where volume does not change is?
- isothermic
- isobaric
- isochoric
Convection does not occur in ?
- liquids
- solids
- gas
Boyle's law states that?
- pressure equals temperature divided by volume
- pressure varies directly with volume
- pressure varies inversely with volume
Charles' Law states that ?
- volume varies directly with temperature
- volume equals pressure * temperature
- volume varies inversely with temperature
The heat required to change a solid to a liquid is called the heat of ?
- vapourisation
- condensation
- fusion
How is heat transferred in a vacuum ?
- Convection
- Radiation
- Conduction
What is the SI units for specific heat capacity ?
- Jkg-1k-1
- J/S/C
- J/ kg
What is 100 Degrees Centigrade in Fahrenheit ?
- 212 Degrees
- 148 Degrees
- 30 Degrees
Dew point is ?
- the temperature at which condensation actually occurs
- the temperature above which condensation occurs
- the temperature below which condensation occurs
The percentage of nitrogen in air is approximately ?
- 0.21
- 0.78
- 0.62
What is 1 btu/lb in joules per kilogram ?
- 9.18 j/kg
- 4128 j/kg
- 2326 j/kg
1 BTU equals ?
- 1055 Joules
- 1055 Calorie
- 1055 kJ
1 calorie is equal to ?
- 400 J
- 4 J
- 40 J
Relative density is ?
- density of water x density of medium
- density of water/density of medium
- density of medium/density of water
The gyroscopic principle is based upon ?
- Newton’s 1st Law
- Newton’s 2nd Law
- Newton’s 3rd Law
Power is the rate of doing work, It is measured in ?
- Joules * Seconds
- Joules/Seconds
- Watts/Seconds
The SI unit for work is the ?
- Horsepower
- Watt
- Joule
An object accelerating down a slope would gain kinetic energy ?
- equal to the potential energy lost
- greater than the potential energy lost
- less than the potential energy lost
What is the ratio of load to effort called ?
- Velocity ratio
- Mechanical advantage
- Mechanical ratio
Which of Newton's laws relates to the formula: Force = mass * acceleration ?
- 3rd
- 1st
- 2nd
An aircraft travels at 500 km/hr for 30 minutes at steady speed. How far does it move in that time ?
- 500 km
- 1000 km
- 250 km
What is the rate of gravity ?
- 9.81 m/s2
- 0.981 m/s2
- 12.7 m/s2
A Scalar quantity has ?
- sense, magnitude and direction
- magnitude only
- sense and direction