Free CTS General Technology Test 1
What causes Alien Crosstalk (AXT) in network systems?
Alien Crosstalk (AXT) occurs when signals from one cable cross over into adjacent cables due to electromagnetic interference. This interference is more likely when UTP (Unshielded Twisted Pair) cables are bundled or packaged alongside other UTP wires, increasing the risk of signal degradation and interference between the cables.
Which of the following lists standards for measuring light?
Candela (cd), Lux (lx), and Nits (nt) are all units of measurement related to light:
*Candela (cd) measures luminous intensity, which is the amount of light emitted in a particular direction.
*Lux (lx) measures illuminance, which is the amount of light falling on a surface area.
*Nits (nt) measure luminance, which is the brightness of a surface or display.
These standards are used in various applications to quantify different aspects of light intensity and brightness.
There is concern about the noise level in an AV rack room. What weight setting on the SPL meter should be used to demonstrate that the noise level doesn't require hearing protection at all times?
A Weighted measurement on an SPL meter is used to approximate the sensitivity of the human ear to different frequencies of sound. It is typically used for general noise level measurements and is suitable for assessing noise levels to determine if hearing protection is required. In environments like AV rack rooms where noise levels can vary, using A Weighted measurements helps in ensuring that the noise levels are within safe limits without necessitating constant hearing protection.
A common equalizer:
A common equalizer in audio processing is typically designed to adjust the amplitude of frequencies within specific bands. A one-third-octave equalizer divides the audio spectrum into bands that are one-third of an octave wide, allowing for precise frequency adjustments. This level of granularity is common in professional audio settings where fine-tuning of audio frequencies is necessary for optimal sound quality and clarity.
When applying the inverse square law to measurements of sound pressure level:
According to the inverse square law of sound propagation, the sound pressure level decreases by 6 decibels (dB) when the distance from the sound source is doubled. This is because sound waves spread out spherically, so the energy per unit area decreases as the distance increases, resulting in a decrease in sound intensity and thus a reduction in sound pressure level.
With light, the amplitude is perceived as:
In the context of light, amplitude refers to the intensity or magnitude of the light waves. The perception of amplitude in light is primarily associated with brightness—the higher the amplitude of light waves, the brighter the perceived light. Brightness corresponds to the amount of light emitted or reflected by an object or source, influencing how luminous or intense the light appears to an observer.
What factors should be addressed while selecting a DC power source for long-distance operation?
When selecting a DC power source for long-distance operation, one of the critical factors to consider is voltage drop. Voltage drop refers to the reduction in voltage as electricity travels through the cables over a distance. For long-distance operation, especially with DC power, minimizing voltage drop is crucial to ensure that the devices receive adequate and stable voltage levels for proper operation. This consideration helps in maintaining the efficiency and reliability of the power supply over extended distances.
The brightness controls on a display adjust which level?
The brightness controls on a display adjust the black level, which refers to the intensity of the darkest parts of the image. Increasing the brightness can raise the black level, making dark areas appear lighter or more grayish. Decreasing the brightness lowers the black level, making dark areas appear darker and more defined. Adjusting the black level is crucial for achieving optimal contrast and detail in the displayed image.
Which system is used to show colors from a video display?
The additive color system is used in video displays to create colors by combining different intensities of red, green, and blue (RGB) light. In this system, when all three colors are combined at full intensity, they produce white light. This is the primary color model used in digital displays such as monitors, projectors, and television screens.
Projectors may use different lamp technologies for different reasons. For a long life without changing the light source, which technology is preferred?
LED (Light-Emitting Diode) lamps are preferred for their long life and reliability without the need for frequent replacements. LEDs have a much longer lifespan compared to other lamp technologies such as halogen, fluorescent, and arc lamps, making them an ideal choice for applications where long-term, maintenance-free operation is important.
Screen gain:
Screen gain refers to the reflective properties of a projection screen that affect how much light is redirected toward the audience. A higher screen gain means that more light is reflected towards the audience, making the image appear brighter. Screen gain is a critical consideration in projection setups to optimize image brightness and visibility, especially in environments with ambient light.