BSNL TTA Online Mock 1

A modem is a device that modulates and demodulates signals in a communication line. It takes digital data from a computer and converts it into analog signals for transmission over telephone lines. At the receiving end, it demodulates the analog signals back into digital data that can be understood by the computer. Therefore, a modem serves both as a modulator and a demodulator in a communication line.

The circuit shown below is a low pass filter because it allows low-frequency signals to pass through while attenuating or blocking high-frequency signals. This is achieved by using a combination of resistors and capacitors in the circuit configuration. The capacitors act as a frequency-dependent impedance, allowing high-frequency signals to bypass the output, while the resistors limit the flow of current for high-frequency signals. As a result, the circuit effectively filters out high-frequency components, making it a low pass filter.

When radio waves pass through the atmosphere, they encounter different layers of air with varying densities. As the density of air changes, it causes the radio waves to change their direction or bend, a phenomenon known as refraction. Additionally, the dielectric constant and refractive index of the atmosphere also change due to factors like temperature, humidity, and pressure. These changes in the dielectric and refractive index further contribute to the refraction of radio waves in the atmosphere. Therefore, the correct answer is "dielectric and refractive index changes".

The correct answer is sailor because "The Periplus of the Erythraean Sea" is an ancient Greek text that provides a detailed account of navigation and trade in the Indian Ocean region. It includes information about various ports, trade routes, and the commodities traded during that time. As a sailor, the author would have had firsthand experience and knowledge of these maritime activities, enabling them to accurately document and describe them in the text.

A low pass filter allows low-frequency signals to pass through while attenuating high-frequency signals. This behavior is similar to an integrator, which sums up the input signal over time, resulting in an output signal that is the integral of the input. On the other hand, a high pass filter allows high-frequency signals to pass through while attenuating low-frequency signals. This behavior is similar to a differentiator, which calculates the rate of change of the input signal over time, resulting in an output signal that is the derivative of the input. Therefore, the correct answer is "Integrator, differentiator."

A tank circuit is a parallel LC circuit because it consists of an inductor (L) and a capacitor (C) connected in parallel. In this configuration, the inductor and capacitor interact with each other to create a resonant frequency, at which the circuit exhibits high impedance. This allows the tank circuit to selectively filter certain frequencies and pass them through while blocking others.

Bridge Duplex works on the principle of potential balance. In potential balance, the bridge circuit is balanced when the potential difference across the two arms of the bridge is equal. This means that the ratio of the resistances in the bridge arms is maintained at a constant value. By adjusting the resistances in the bridge arms, the potential balance can be achieved, allowing for accurate measurements of unknown resistances.

In a P-type semiconductor, the Fermi level lies at the top of the valence band. This is because P-type semiconductors are doped with impurities that introduce excess holes, which are positively charged. These holes have a higher energy level than the valence band, and therefore the Fermi level is pushed towards the top of the valence band.

A delay equalizer is a band pass filter because it allows a specific range of frequencies to pass through while attenuating frequencies outside of that range. This is useful for compensating for delays in a signal by selectively boosting or cutting certain frequencies. A high pass filter would only allow high frequencies to pass through, a low pass filter would only allow low frequencies to pass through, and an all pass filter would allow all frequencies to pass through without attenuation.

Above the Curie temperature, ferromagnetic materials lose their spontaneous magnetization and behave like paramagnetic materials. In paramagnetic materials, the magnetic moments of individual atoms align with an external magnetic field, but they do not retain their alignment when the field is removed. This is in contrast to ferromagnetic materials, where the magnetic moments align even in the absence of an external field. Therefore, the correct answer is paramagnetic.

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The word "affluent" means having a lot of money or wealth. The synonym for this word is "prosperous", which also means having a lot of money or being successful financially. Therefore, the correct answer is "prosperous".

Silicon Iron is not a permanent magnetic material because it is a soft magnetic material. Soft magnetic materials like silicon iron have low coercivity, which means they can be easily magnetized and demagnetized. Permanent magnetic materials, on the other hand, have high coercivity and can retain their magnetization over a long period of time. Therefore, Silicon Iron does not fall under the category of permanent magnetic materials.

The correct answer is 400 cps. This means that the number of unattainable tones has a frequency of 400 cycles per second.

Metallic copper is a diamagnetic substance because it does not possess any unpaired electrons. Diamagnetic substances are repelled by a magnetic field and do not retain any magnetic properties when the external field is removed.

In an SSB (Single Sideband) transmitter, a class B RF amplifier is most likely to be found. This type of amplifier is commonly used in RF applications due to its high efficiency and ability to amplify signals with minimal distortion. Class B amplifiers use a push-pull configuration where one transistor amplifies the positive half of the input signal and another transistor amplifies the negative half. This allows for efficient amplification of RF signals while minimizing power consumption.

The dial tone has a frequency of 33 cps. This means that the dial tone produces 33 sound waves per second. The frequency of the dial tone is important for telephone communication as it helps to establish a clear connection between callers. A dial tone with a frequency of 33 cps is commonly used in telephone systems to indicate that the line is open and ready for dialing.

Coercivity refers to the magnetic field strength required to completely remove the residual magnetization in a material. It is a measure of how difficult it is to demagnetize a material. When the coercivity is high, it means that a stronger magnetic field is needed to demagnetize the material. In this context, the correct answer is "Coercivity" because it specifically mentions the magnetic field required to reduce the residual magnetization to zero.

The word "falter" is the correct synonym for "limp". "Falter" means to move unsteadily or stumble, which is similar to the way a person with a limp might walk. The other options, "kneel", "bend", and "stoop", do not accurately convey the meaning of "limp".

Puhar was the important Chola port during Karikala's rule. This port played a significant role in the maritime trade and commerce of the Chola Empire. It was strategically located on the east coast of Tamil Nadu, making it easily accessible for trade with other regions. Puhar was known for its bustling harbor, where ships from various parts of the world would dock, bringing in goods and facilitating cultural exchange. The port of Puhar was a vital hub for the Chola Empire's economic prosperity and expansion.