3272-2 Phy (2.6)

A material, which has a varying refractive index is a. step index. single index. double index.

A ray of light that travels through the centre of curvature of a concave mirror before being reflected, how is it reflected?. Through the focal point. Through the focal point and centre of curvate. Through the centre of curvature.

What will the image produced through a divergent lens be?. Negative. Real. Virtual.

When a beam of light passes from one medium to another with a different refractive index, what will happen to the beam of light?. Total internal reflection. Change speed. Total internal refraction.

A fibre optic cable has different refractive indexes across its core diameter, it is a. single mode fibre. graded index fibre. step index fibre.

Incident light travelling from air to water, the light is. bent towards the normal. not bent. bent away from the normal.

If a light is beamed at a flat mirror, what is the angle it reflects at?. Reflective index. Angle of incidence. Reactive angle.

In a graded index multimode fibre is the refractive index. is high. varies high and low. is low.

The fibre optic receiver is a. photodiode.. laser diode. light emitting diode.

The usable bandwidth of a fibre is determined by. the wavelength of the light. the angle of total internal reflection. the intermodal dispersion.

If, with a concave mirror the image is placed beyond the centre of curvature, the image produced will be. virtual, erect and larger. real, inverted and smaller. real, erect and larger.

The power of a lens is calculated from the. reciprocal of the focal length. product of the focal length and its distance from the pole. focal length squared.

Single mode optical fibre cable will. have several light rays to pass. have diameter matched to wavelength of light passed. cause distortion to the light wave at the output end which is dependent upon the length of the cable.

When an emergent light wave enters a divergent len. it will focus beyond the lens. it will focus behind the lens. it is s spherical.

In a concave mirror, a light ray passing through the focal point will be reflected. through the focal point. on the centre line of the mirror. parallel to the axis.

A passive sensor. does not require power. requires power for the sensor. requires power for the transmitter.

Refractive index is. lower for 4oC water than 0oC ice. higher for diamond than acrylic. highest for water.

For optical fibres, the refractive index of the cladding compared to that of the core. can be either bigger or smaller depending on specification. is always smaller. is always larger.

The ability for a fibreoptic cable to carry waves is dependent on. material, absorption and speed of light. internal reflection. material, diameter and absorption.

In spherical aberrations. incident rays further from the axis intersect slightly closer to the lens to produce a distorted picture. incident rays further from the axis intersect slightly further away from the lens to produce a distorted picture. the bending of light through lens intersect at the same point (achromatic lens).

In a fibre optic flying control system. the sensor and transmitter require electrical power. the sensor inputs to the transmitter which needs electrical power. the sensor needs electrical power.

In fibreoptics, the type of cable is chosen by. the strength of signal needed. matching the diameter of the cable with the wavelength. distance required to travel.

When refraction takes place. the frequency remains constant. the speed of the wave remains constant. the wavelength remains constant.

When light meets a Glass / Air boundary at an angle of incidence less than the critical angle. both reflection and refraction takes place. no light is reflected. total Internal Reflection takes place.

An obj ect placed more than twice the focal length beyond a converging lens will form an image that is. inverted, larger and virtual. inverted, smaller and real. erect, smaller and real.

A parabolic mirror may be used to prevent. lateral inversion. spherical aberration. formation of a penumbra.

The refractive index for air is approximately. 0. 1. 10.

In optical fibres the total internal reflection of light only occurs at angles ritical angle. less than the critical angle. equal to the critical angle. greater than the critical angle.

In a concave mirror, if an object is placed between the focal point and the pole, the image will be. real, erect and diminished. virtual and on the opposite side. real, inverted and larger.

The purpose of a patch cord used with an OTDR is. to compensate for any contraction of the Fiber optic cable during test. to overcome the dead zone problem caused by reflection at OTDR launch connector. to attenuate OTDR output power which could cause damage to the cable under test.

The power of a lens is measured in. Lumens per Watt. Watts. Diopters.

For a concave lens, the image is. virtual. real. a chromatic orb.

Lasers use which source of light?. Scattered. Refraction. Coherent.

Illumination of one lumen per metre squared is one. luxor. lux. candle.

The amount of light emitted by a lamp can be measured in. candle's. luxors. lumens.

The light gathering power of a lens is indicated by its. material. thickness of the lens. focal ratio.

In order for a converging lens to form a real image, the object distance must be more than. focal length. 5 times the thickness of the lens. 1 inch.

A ______ lens is thicker in the middle than at the edges. converging. concave. upsharp.

When is the only time a concave mirror forms a virtual image?. When the object is at the focal point. When the object is inside the focal point. When the object is placed at the center of curvature.

A convex mirror forms a virtual image when. the object is at the centre of curvature. the object is inside the focus. always.

A Concave mirror is used in. a rear view mirror. a periscope. headlights.

When the movement of an object rotating around a radius at a constant speed is projected onto a plane, the projected image follows what path?. Sinusoidal. Lateral. Longitudinal.

The speed of sound in air at 0 °C is approximately. 331 m/s. 3 * 108 m/s. 181 m/s.

If a wave traveling to a point meets a wave traveling from that point, of equal frequency. the two waves cancel each other out. they will have no effect on each other. a standing wave is formed.

Quality of sound depends upon. pure sound waves being produced by the source. frequency and harmonics of the waves being produced. quality of the receiver.

Particles vibrating in air. tend to give off heat. tend to give off light. produce waves.

The fundamental frequency is the. 1st harmonic. 2nd harmonic. 3rd harmonic.

The first overtone of a sound wave is the. 1st harmonic. 2nd harmonic. fundamental frequency.

Two pure tones of similar frequency are heard by a person. What will they hear?. One pure tone. A beat of the two tones. Two tones.

Two sound waves of the same frequency and amplitude are moving half a wavelength out of phase with each other. What will be heard?. Nothing. Twice the volume of one of the sound waves. Half the volume of one of the sound waves.

A fire engine is approaching you with its siren on. As it passes you its pitch. stay the same. increases. decreases.

Quality of sound is dependant on. number and pitch of harmonics. medium it is travelling through. frequency of the supply.

What frequency is a tone which is 4 times the fundamental frequency?. 2nd overtone. 3rd overtone. 3rd harmonic.

Intensity of sound waves. is not affected by distance. varies inversely as the square of distance from source. vary directly as per distance from source.

In a standing wave the point where continuous vibration of maximum amplitude occurs is called the. harmonic. anti-node. node.

The name given to sounds below that which the human ear can detect, i.e. below 20Hz is. ultra sound. infra sound. sonic pitch.

The speed of sound in dry air is 331 m/s. In a solid the speed would. increase. decrease. stay the same.

If a tuning fork is struck and held close to the ear and slowly rotated about the vertical axis, in one rotation how many times is there no sound?. 2. 4. Sound is audible for the whole revolution.

What is the phenomenon that occurs when a siren that approaches you, at the point of passing, the pitch decreases?. Resonance. Doppler effect. Echo.

For hearing protection, noise cancelling headphones. cannot reduce the noise from outside completely. operate by destructive interference of sound waves. operate by constructive interference of sound waves.

Tuning forks are used to vibrate musical instruments because. they produce both of the other effects described. they produce a beat when played together with the instrument. they produce a pure note.

When an open pipe is played and a note is heard. the lowest frequency of the note is called second harmonic. resonance occurs with standing waves set up inside the pipe. there is a 180o phase change at the open end.

Two sound waves are the same but slightly out of phase. This means that. the beat frequency is the same. there will be no beat frequency. the beat frequency will be slightly different.

In a vibrating string, the point at which there is no displacement is called a. antinode. node. fundamental mode.

The amplitude of a Transverse Wave is the distance from. the top of a peak to the bottom of a trough. half the distance from peak to trough. one peak to the next.

Increasing the Amplitude of a sound wave increases its. pitch. moment. loudness.

wave in which the vibrations are perpendicular, or at right angles to the direction of wave travel is a. Dispersion Wave. Longitudinal Wave. Transverse Wave.

When a string vibrates, the point at which maximum displacement occurs is called the. node. antinode. primary node.

Increasing the frequency of a sound wave increases its. pitch. loudness. moment.

A wave in which the vibrations are parallel to, or along, the direction of travel is a. Transverse Wave. Upright Wave. Longitudinal Wave.

If a string is vibrating at the 3rd harmonic, it will be oscillating at. Fundamental Frequency. 4 times its fundamental frequency. 3 times its fundamental frequency.

The varying pitch of the sound of a train passing by is caused by a phenomenon known as. Doppler effect. double frequency. resonance.

Wavelength is. distance from trough to crest. distance between crests. distance between top and bottom.

The speed of sound at standard atmospheric temperature and pressure is. 34 Km/s. 340 m/s. 340 Km/s.

In which medium does sound travel the fastest?. Steel. Air. Water.

Which has the most effect on the speed of sound in air?. Temperature. Wavelength. Frequency.

The fundamental frequency of a control cable is 10 Hz, the frequency of the 2nd Harmonic is. 10 Hz. 20 Hz. 20 KHz.

Which of the following is an example of a Longitudinal Wave?. Sound Wave. Radio Wave. Light Wave.

What is the wavelength of a note of frequency 1kHz when its velocity is 340m/s?. 0.34m. 3.4m. 0.34km.

A body drops from 10m, it will hit the ground in. 1 Second. 2 seconds. √2 seconds.

What height of water is equivalent to 1 atmosphere?. 29ft. 33ft. 101ft.

10 BTU is equivalent to. 570 Joules. 10,550 Joules. 63,560 Joules.

What does 'temperature of a body' mean?. Its hotness. How it radiates heat. Its ability to retain heat.

In fibre optics. The fibre cable has a refractive index of 1.5, what is its speed?. 300 meters/microsecond. 400 meters/microsecond. 200 meters/microsecond.