To calculate the tailstock set-over for turning a taper, we use the formula that relates the taper ratio, the length of the job, and the set-over amount. The taper ratio is given as 1 in 10, meaning for every 10 units of length, there is a 1 unit change in diameter. The set-over is half of the total taper per unit length multiplied by the job length.
Understand the given taper ratio: The taper is 1 in 10. This means that for every 10 mm of length, the diameter changes by 1 mm. So, the taper per unit length is \(\frac{1}{10}\).
Identify the length of the job: The length of the job is given as 60 mm.
Recall the formula for tailstock set-over: The tailstock set-over (\(S\)) is calculated as half of the total taper over the length of the job. The formula is:
\[ S = \frac{\text{Taper Ratio}}{2} \times \text{Length of Job} \]Substitute the values into the formula:
\[ S = \frac{1/10}{2} \times 60 \]Calculate the set-over:
\[ S = \frac{1}{20} \times 60 \]\[ S = \frac{60}{20} \]\[ S = 3 \text{ mm} \]Therefore, the tailstock set-over required is 3 mm.
B) 3 mm is the correct answer, as calculated using the standard formula for tailstock set-over with the given taper ratio and job length.
This question asks about the location of the maximum flame temperature in a typical flame, such as that produced by a Bunsen burner or a gas torch. Understanding the different zones of a flame and the combustion processes occurring in each zone is key to answering this question.
Therefore, the maximum flame temperature occurs in the region where complete combustion is most efficient, which is just above the tip of the inner cone.
Correct Option: B) At the inner cone
The hottest part of the flame is actually just above the tip of the inner cone, where the primary combustion products mix with sufficient oxygen from the surrounding air to achieve complete combustion. While the option states "At the inner cone," in the context of typical multiple-choice questions about flame temperature, "at the inner cone" often refers to the region immediately surrounding or just above its tip, which is the zone of maximum temperature. The inner cone itself is cooler, but its tip and the region immediately surrounding it are where the peak temperature is achieved due to complete combustion.
The question asks for an alternative name for "Down milling". This requires knowledge of the different types of milling operations and their common terminology.
B) Climb milling — As explained above, climb milling is characterized by the cutter rotating in the same direction as the workpiece feed, and it is also known as down milling.
The question asks about the manufacturing process for bolt heads. We need to identify the metal forming process that is specifically used to create an enlarged head on a shaft or rod, like a bolt head.
Correct Option: D) Upset forging — This process involves increasing the cross-sectional area of a material by applying compressive force along its length. This is precisely how the head of a bolt is formed from a rod or wire.
The resistance of a conductor is determined by its physical properties and dimensions. We need to recall the formula for resistance and analyze how each given factor influences it.
Therefore, the resistance does not depend on the specific shape of the cross-section, only its area.
Correct Option: A) Shape of cross section
The question asks to identify which of the given options is NOT a resistance welding process. We need to understand the principle of resistance welding and then classify each option accordingly.
D) Carbon arc — Carbon arc welding is an arc welding process that uses an electric arc between a carbon electrode and the workpiece to generate heat for welding. It does not rely on the electrical resistance of the workpieces for heat generation, which is the defining characteristic of resistance welding processes.
The no-load speed of a DC motor is primarily determined by its speed regulation characteristics, which are influenced by the magnetic flux. We need to analyze how the flux changes at no-load for each type of DC motor.
Comparing these, the series motor has the potential for the highest no-load speed, to the point of being dangerous.
B) Series motor — A series motor has its field winding in series with the armature. At no-load, the armature current (and thus the series field current) becomes very small. This results in a very weak magnetic field (flux). Since the speed of a DC motor is inversely proportional to the flux (\(N \propto 1/\phi\)), a very low flux causes the motor to accelerate to an extremely high, dangerous speed, often referred to as a "runaway" condition. Therefore, series motors are never operated without a mechanical load.
The question asks where iron losses occur in a DC motor. Iron losses (or core losses) are a type of energy loss that occurs in the magnetic core of electrical machines due to alternating magnetic fields. We need to identify the component in a DC motor that experiences these alternating fields.
Correct Option: B) Armature. Iron losses (hysteresis and eddy current losses) occur in the armature core of a DC motor because it is subjected to a continuously changing magnetic field as it rotates.
To determine the number of poles in a 3-phase induction motor, we use the relationship between synchronous speed, frequency, and the number of poles. We are given the operating frequency and the running speed of the motor. First, we need to find the synchronous speed, and then we can calculate the number of poles.
For an induction motor, the rotor speed \(N_r\) is always slightly less than the synchronous speed \(N_s\). The synchronous speed is the speed at which the magnetic field rotates.
Since the motor is running at \(1500 \, \text{rpm}\), the synchronous speed \(N_s\) must be the nearest standard synchronous speed greater than \(1500 \, \text{rpm}\) for a 50 Hz supply. Common synchronous speeds for 50 Hz are:
Given that the motor is running at \(1500 \, \text{rpm}\), its synchronous speed must be \(1500 \, \text{rpm}\). This implies that the slip is zero, which is an ideal condition, but for the purpose of finding the number of poles from the running speed, we assume the running speed is very close to the synchronous speed, or in this specific case, exactly the synchronous speed for a certain pole configuration.
The synchronous speed \(N_s\) (in rpm) is given by the formula:
\[ N_s = \frac{120 \times f}{P} \]where:Rearrange the formula to solve for \(P\):
\[ P = \frac{120 \times f}{N_s} \]Now, substitute the values: \(f = 50 \, \text{Hz}\) and \(N_s = 1500 \, \text{rpm}\).\[ P = \frac{120 \times 50}{1500} \]\[ P = \frac{6000}{1500} \]\[ P = 4 \]C) 4 is the correct number of poles for a 3-phase induction motor operating at 50 Hz and having a synchronous speed of 1500 rpm.
The question asks about the thermodynamic cycle on which a typical power plant operates. We need to identify the cycle that best describes the working principle of thermal power plants, which commonly use steam as the working fluid.
Correct Option: D) Rankine cycle — The Rankine cycle is the fundamental thermodynamic cycle for all steam power plants, which are the most common type of thermal power plants. It efficiently converts heat into work using a working fluid that undergoes phase changes (liquid to vapor and back).