The question asks to identify the timber suitable for making sports goods. This requires knowledge of the properties of different types of wood and their common applications.
Correct Option: A) Mulberry is widely recognized for its excellent strength, flexibility, and shock-absorbing qualities, making it ideal for manufacturing various sports goods like cricket bats, hockey sticks, and tennis rackets.
The question asks to classify cement concrete based on its material properties, specifically its response to stress and strain over time. We need to understand the definitions of elastic, plastic, and visco-elastic materials.
B) Visco-elastic material. Cement concrete exhibits both elastic and viscous properties. It deforms under load (elastic component) but also shows time-dependent deformation like creep (viscous component) under sustained loading and stress relaxation. Therefore, it is correctly classified as a visco-elastic material.
The question asks to identify the instrument used for measuring discharge. Discharge, in fluid mechanics, refers to the volume of fluid flowing per unit time. We need to evaluate each option based on its primary function.
B) Venturimeter is used to measure the discharge (rate of flow) of a fluid in a pipe. It operates by creating a pressure differential that is proportional to the flow rate, based on Bernoulli's principle.
The question asks about the characteristics of the direct method of contouring. We need to evaluate each option based on the known properties of this surveying technique.
Correct Option: C) Most accurate method
The direct method involves actually locating points of the same elevation on the ground and then plotting them. This direct approach ensures that the contour lines drawn are very precise and accurately represent the terrain's elevation, making it the most accurate method of contouring.
The question asks about the plasticity index of different soil types. The plasticity index is a measure of the plasticity of a soil, which is its ability to undergo deformation without cracking or crumbling. This property is primarily influenced by the particle size and mineralogy of the soil.
Correct Option: C) Clay
The question asks about the primary purpose of seasoning timber. Seasoning is a crucial process in timber preparation, and understanding its goals helps identify the correct option.
D) Remove sap from the timber — Seasoning primarily involves drying the timber to remove moisture (sap) from its cells. This process prevents decay, reduces shrinkage and warping, and improves the strength and stability of the wood.
The question asks which type of instrument's range can be extended using instrument transformers. Instrument transformers (current transformers - CTs and potential transformers - PTs) are primarily used to measure large alternating currents and voltages safely and accurately by stepping them down to measurable levels for standard low-range instruments.
A) induction instrument — Induction instruments are primarily AC instruments, and their range for measuring high currents and voltages is commonly extended using current transformers (CTs) and potential transformers (PTs).
The question asks which principle cannot be used to design a wattmeter. A wattmeter measures electrical power, which is the product of voltage and current. We need to evaluate the fundamental working principles of each instrument type listed and determine if they can effectively measure power.
Correct Option: C) moving iron instrument
An energy meter measures electrical energy consumption. It consists of a rotating disc whose speed is proportional to the power being consumed. To ensure accurate measurement, the disc's rotation needs to be controlled. This control is achieved by balancing the driving torque (which causes rotation) with a braking torque (which opposes rotation).
D) maintain steady speed and equal to driving torque. The primary function of the braking torque in an energy meter is to balance the driving torque, thereby ensuring that the disc rotates at a steady speed directly proportional to the power being measured. This balance is essential for accurate energy integration.
The question asks about the instruments used to measure electrical resistance. We need to identify which of the given options are specifically designed for this purpose.
D) ohmmeters and resistance bridges. Ohmmeters are common devices for direct resistance measurement. Resistance bridges (e.g., Wheatstone bridge) provide very accurate measurements of resistance, especially for precision applications.