2. Physics - Q&A

What is the thickness of a single mode fibre optic?

• 50 micrometres
• 5 micrometres.
• 15 micrometres

An aircraft of 2 metric tonnes uses 800 kilojoules kinetic energy to make an emergency stop. Its brakes apply a force of 10 kiloNewtons. What distance does it travel before it comes to a stop?

• 40m.
• 8 m.
• 80m.

A lifting machine moves with an effort, a distance of 200 cm, in order to raise it 0.5 m. The Velocity Ratio is

• 8.
• 4.
• 2.

A cylinder filled with water to half a metre will exert a pressure of

• 49.0 Pa.
• 4900 Pa.
• 9800 Pa.

A good refrigerant has

• high condensing pressure, low evaporating temperature.
• high condensing pressure, high vaporating temperature.
• low condensing pressure, low vaporating temperature.

Oxygen, atomic number 8 is

• monovalent.
• covalent.
• bivalent.

An atom with 5 electrons in its outer shell is

• trivalent.
• univalent.
• pentavalent.

A light aircraft flies in a semi-circle from point A to point B. If the circle has a radius of 20km and the time taken is 30 minutes, the average speed is

• 125.7 km/h.
• 251.4 km/h.
• 62.83 km/h.

What is the atomic number of the element shown here?

• 7.
• 3.
• 4.

1000 lb/in2 is in an accumulator. If 3000 lb/in2 of hydraulic fluid is pumped in, what is the pressure on the air side?

• 3000 lb/in2.
• 4000 lb/in2.
• 1000 lb/in2.

A good refrigerant has a

• low condensation temperature and high condensation pressure.
• low condensation temperature and low condensation pressure.
• high condensation temperature and low condensation pressure.

The standard temperature and pressure for measuring the volume of liquids and solids is

• 20 degrees C and 700 mmHg.
• 20 degrees C and 760 mmHg.
• 15 degrees C and 760 mmHg.

The landing speed of an aircraft is 54 m/s. If the maximum deceleration is 3m/s2 the minimum length of runway required is

• 162m.
• 486m.
• 360m.

Which has the greatest volume?

• 1 kg of water at 0 degreesC has a greater volume than 1 kg of ice at the same temperature.
• 1 kg of ice at 0 degreesC has a greater volume than 1 kg of water at the same temperature.
• Both 1 kg of ice at 0 degreesC and 1 kg of water at 0 degreesC have the same volume.

A vessel has 25 ml of water which produces 10 kPa. If another 125 ml of water is added, what will be the pressure in the vessel?

• 40kPa
• 50kPa
• 60kPa

What do you get when you add 2H2 and O?

• 2H O2
• 2H2 O
• H2 O2

A mass of 20kg produces a momentum of 300kgm/s. What is the Kinetic energy?

• 3250 Joules.
• 2250 Joules.
• 4500 Joules.

A force perpendicular to a beam produces what type of stress?

• axial.
• shear.
• radial

As a block of ice is melted (to 4 degrees C). Its volume

• stays same.
• decreases.
• increases.

A lever of length 105 cm is used with a fulcrum placed 15 cm from the end bearing the load. Its mechanical advantage is

• 9.
• 7.
• 6.

A body starting from rest accelerates at the rate of 20 metres per second squared. What is the distance covered until the body reaches a velocity of 50 metres per second?

• 6.25 metres.
• 25.0 metres.
• 62.5 metres.

A body rotating at an angular velocity of 5 radians/sec, with a radius of 5 metres has a speed of

• 5pi metres per second.
• 5 metres per second.
• 25 metres per second.

If, with a concave mirror the object is placed beyond the centre of curvature, the image produced will be

• virtual, erect and larger.
• real, inverted and smaller.
• real, inverted and enlarged.

The oscillation produced by a pendulum 2500mm long has a periodic time of

• 6 seconds.
• 3 seconds.
• 9 seconds.

You are at the north pole where the temperature is minus 50 degrees C below freezing. What sort of thermometer would you use to measure it?

• Water.
• Alcohol.
• Mercury.