1. Bernoulli's theorem is based on energy conservation; option [B]. It states that in a flowing fluid, the total mechanical energy per unit mass remains constant along a streamline. This principle describes the relationship between fluid velocity, pressure, and elevation and is fundamental in fluid dynRead more

    Bernoulli’s theorem is based on energy conservation; option [B]. It states that in a flowing fluid, the total mechanical energy per unit mass remains constant along a streamline. This principle describes the relationship between fluid velocity, pressure, and elevation and is fundamental in fluid dynamics, aerodynamics, and hydrodynamics. Bernoulli’s theorem helps analyze fluid flow in various engineering applications, including aircraft design, pipe flow, and hydraulic systems. It is derived from the conservation of energy principle, where the total energy of a system remains constant unless acted upon by external forces. Therefore, the correct option is [B] Energy conservation, elucidating the foundational principle upon which Bernoulli’s theorem is based.

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  2. An iron needle floats on the surface of water due to surface tension; option [B]. Surface tension arises from the cohesive forces between water molecules, particularly at the water-air interface. This cohesion creates a thin film on the water's surface with higher tension than the bulk of the liquidRead more

    An iron needle floats on the surface of water due to surface tension; option [B]. Surface tension arises from the cohesive forces between water molecules, particularly at the water-air interface. This cohesion creates a thin film on the water’s surface with higher tension than the bulk of the liquid. The surface tension acts like a “skin,” supporting lightweight objects such as the iron needle, allowing it to float. Unlike other materials, the iron needle’s density is higher than that of water, so it would typically sink. However, the strong surface tension of water counteracts the needle’s weight, effectively “holding it up” on the water’s surface. This phenomenon is observed in various contexts, from small insects walking on water to certain lightweight objects floating. Therefore, the correct option is [B] Due to surface tension, as it is the cohesive force at the water’s surface that enables the iron needle to float rather than sink.

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  3. Absorption of ink by blotting paper involves the capillary reaction phenomenon; option [B]. Capillary action occurs due to the cohesive and adhesive forces between the liquid molecules and the fibers of the paper. This interaction causes the ink to be drawn upward through the small pores in the papeRead more

    Absorption of ink by blotting paper involves the capillary reaction phenomenon; option [B]. Capillary action occurs due to the cohesive and adhesive forces between the liquid molecules and the fibers of the paper. This interaction causes the ink to be drawn upward through the small pores in the paper, facilitating its absorption. Capillary action is crucial in processes like ink absorption in blotting paper, where it efficiently pulls the ink into the paper fibers. Viscosity of the ink refers to its resistance to flow and is not directly related to the adsorption process. Diffusion of ink through blotting involves the movement of ink molecules through the paper, which is not the primary mechanism in ink absorption by blotting paper. Siphon action requires a continuous flow of liquid, which is not applicable to the absorption of ink by blotting paper. Therefore, the correct option is [B] Capillary Reaction phenomenon.

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  4. Action and reaction have the same magnitude and opposite directions; option [D]. According to Newton's third law of motion, when one object exerts a force on another object (action), the second object exerts an equal but opposite force on the first object (reaction). These forces act on different obRead more

    Action and reaction have the same magnitude and opposite directions; option [D]. According to Newton’s third law of motion, when one object exerts a force on another object (action), the second object exerts an equal but opposite force on the first object (reaction). These forces act on different objects, have equal magnitudes, and opposite directions. Therefore, all options are correct: [A] Work on two different objects, [B] Have the same magnitude, and [C] Have opposite directions. This fundamental principle of action and reaction is essential in understanding the dynamics of interactions between objects and is applicable in various fields of physics and engineering. It elucidates how forces are transmitted between objects and plays a critical role in analyzing and predicting the motion of systems governed by Newtonian mechanics.

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  5. To cover the maximum horizontal distance, a ball should be thrown at a 45° angle from the horizontal; option [D]. At this angle, the horizontal and vertical components of the initial velocity are equal, leading to the greatest range for a projectile launched with the same initial speed. Therefore, tRead more

    To cover the maximum horizontal distance, a ball should be thrown at a 45° angle from the horizontal; option [D]. At this angle, the horizontal and vertical components of the initial velocity are equal, leading to the greatest range for a projectile launched with the same initial speed. Therefore, the correct option is [D] 45°. This principle is derived from the equations of projectile motion and is applicable in various contexts, from sports like basketball and javelin throwing to engineering applications such as projectile motion calculations. Understanding the optimal launch angle for maximum range is essential for achieving desired distances in projectile motion scenarios, making it a fundamental concept in physics and practical applications. Thus, launching the ball at a 45° angle ensures it travels the farthest horizontally compared to other angles listed.

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