Option B: Electrical energy is produced by converting solar energy using photovoltaic cells. Photovoltaic cells, commonly known as solar cells, directly convert sunlight into electricity through the photovoltaic effect. When sunlight strikes the semiconductor material within the cells, it excites elRead more
Option B: Electrical energy is produced by converting solar energy using photovoltaic cells. Photovoltaic cells, commonly known as solar cells, directly convert sunlight into electricity through the photovoltaic effect. When sunlight strikes the semiconductor material within the cells, it excites electrons, creating an electric current. This process occurs within the p-n junction of the semiconductor, where electrons are knocked loose from their atoms, creating electron-hole pairs. These electrons are then forced to flow in one direction by an internal electric field, generating a direct current (DC) output. This electrical energy can be used to power various devices, homes, or even entire electrical grids when connected in arrays.
Options A (optical energy), C (thermal energy), and D (mechanical energy) are incorrect as they do not accurately describe the output of photovoltaic cells. Optical energy refers to light energy, which is the input to the photovoltaic cells rather than the output. Thermal energy refers to heat energy, and mechanical energy refers to energy associated with the motion of objects, neither of which is produced directly by photovoltaic cells. Therefore, the correct answer is option B, electrical energy, as it is the primary output of photovoltaic cell conversion of solar energy.
Option C: Stored energy is found in a substance like a rubber mattress when its shape changes as we sit or lie on it. In this context, the stored energy refers to elastic potential energy, which arises due to the deformation of the rubber material. When we apply force to the rubber mattress by sittiRead more
Option C: Stored energy is found in a substance like a rubber mattress when its shape changes as we sit or lie on it. In this context, the stored energy refers to elastic potential energy, which arises due to the deformation of the rubber material. When we apply force to the rubber mattress by sitting or lying on it, the material undergoes deformation, causing it to temporarily store energy within its structure. This stored energy is potential energy because it has the potential to do work or return to its original shape when the external force is removed. In the case of the rubber mattress, the stored elastic potential energy allows the material to exert a restoring force, attempting to return to its original shape, once the weight is removed. This property of rubber, known as elasticity, enables it to absorb and release energy, making it useful in various applications like shock absorbers, springs, and cushioning materials. Therefore, the correct answer is option C, stored energy, specifically referring to the elastic potential energy stored within the rubber material when its shape changes due to external forces.
The drawn bow does not possess kinetic energy; option [D]. Kinetic energy refers to the energy an object possesses due to its motion. A fired bullet, flowing water, and a moving hammer all exhibit kinetic energy because they are in motion. However, a drawn bow, while potentially storing potential enRead more
The drawn bow does not possess kinetic energy; option [D]. Kinetic energy refers to the energy an object possesses due to its motion. A fired bullet, flowing water, and a moving hammer all exhibit kinetic energy because they are in motion. However, a drawn bow, while potentially storing potential energy due to its tension, lacks kinetic energy until it is released. At the point of release, the potential energy stored in the drawn bow is converted into kinetic energy as the arrow is propelled forward. Prior to release, the bow itself is not in motion and therefore does not possess kinetic energy. Instead, it stores potential energy, which is transformed into kinetic energy upon release, propelling the arrow forward with force derived from the tension stored in the bowstring.
When the speed of a moving object doubles, its kinetic energy quadruples; option [B]. This relationship is due to the fact that kinetic energy is directly proportional to the square of the velocity. According to the kinetic energy formula (K.E. = 1/2 m v^2) doubling the velocity results in the kinetRead more
When the speed of a moving object doubles, its kinetic energy quadruples; option [B]. This relationship is due to the fact that kinetic energy is directly proportional to the square of the velocity. According to the kinetic energy formula (K.E. = 1/2 m v^2) doubling the velocity results in the kinetic energy increasing by a factor of four. This principle is fundamental to understanding the relationship between velocity and kinetic energy in classical mechanics. Therefore, option B, quadruples, is the correct answer. It illustrates the significant impact that changes in velocity can have on the kinetic energy of a moving object. This relationship underscores the importance of velocity in determining the energy associated with the motion of an object, highlighting its role in various physical phenomena and calculations involving kinetic energy.
More energy is spent in climbing stairs because the person works against gravity; option [A]. When climbing stairs, the individual exerts force in the opposite direction to gravity's pull, lifting their body against it. This requires energy expenditure, as work is done to overcome gravity's resistanRead more
More energy is spent in climbing stairs because the person works against gravity; option [A]. When climbing stairs, the individual exerts force in the opposite direction to gravity’s pull, lifting their body against it. This requires energy expenditure, as work is done to overcome gravity’s resistance. In contrast, on flat ground, the person’s horizontal movement doesn’t involve significant gravitational opposition. The gravitational force acts perpendicular to the motion, so no work is done against it, unlike when ascending stairs where gravity opposes vertical motion. Therefore, option A, “the person works against gravity,” accurately explains the increased energy expenditure in stair climbing. This phenomenon aligns with the principle of conservation of energy, where the energy spent in lifting the body against gravity is transformed into potential energy. Consequently, climbing stairs demands more energy compared to walking on level ground due to the additional work required to overcome gravity’s resistance, highlighting the interplay between gravitational forces and human movement in energy expenditure.
Which of the following is produced by converting solar energy using photovoltaic cells?
Option B: Electrical energy is produced by converting solar energy using photovoltaic cells. Photovoltaic cells, commonly known as solar cells, directly convert sunlight into electricity through the photovoltaic effect. When sunlight strikes the semiconductor material within the cells, it excites elRead more
Option B: Electrical energy is produced by converting solar energy using photovoltaic cells. Photovoltaic cells, commonly known as solar cells, directly convert sunlight into electricity through the photovoltaic effect. When sunlight strikes the semiconductor material within the cells, it excites electrons, creating an electric current. This process occurs within the p-n junction of the semiconductor, where electrons are knocked loose from their atoms, creating electron-hole pairs. These electrons are then forced to flow in one direction by an internal electric field, generating a direct current (DC) output. This electrical energy can be used to power various devices, homes, or even entire electrical grids when connected in arrays.
Options A (optical energy), C (thermal energy), and D (mechanical energy) are incorrect as they do not accurately describe the output of photovoltaic cells. Optical energy refers to light energy, which is the input to the photovoltaic cells rather than the output. Thermal energy refers to heat energy, and mechanical energy refers to energy associated with the motion of objects, neither of which is produced directly by photovoltaic cells. Therefore, the correct answer is option B, electrical energy, as it is the primary output of photovoltaic cell conversion of solar energy.
See lessWhen we sit on a seat with rubber mattress or lie down on the mattress, its shape changes. Found in such a substance:
Option C: Stored energy is found in a substance like a rubber mattress when its shape changes as we sit or lie on it. In this context, the stored energy refers to elastic potential energy, which arises due to the deformation of the rubber material. When we apply force to the rubber mattress by sittiRead more
Option C: Stored energy is found in a substance like a rubber mattress when its shape changes as we sit or lie on it. In this context, the stored energy refers to elastic potential energy, which arises due to the deformation of the rubber material. When we apply force to the rubber mattress by sitting or lying on it, the material undergoes deformation, causing it to temporarily store energy within its structure. This stored energy is potential energy because it has the potential to do work or return to its original shape when the external force is removed. In the case of the rubber mattress, the stored elastic potential energy allows the material to exert a restoring force, attempting to return to its original shape, once the weight is removed. This property of rubber, known as elasticity, enables it to absorb and release energy, making it useful in various applications like shock absorbers, springs, and cushioning materials. Therefore, the correct answer is option C, stored energy, specifically referring to the elastic potential energy stored within the rubber material when its shape changes due to external forces.
See lessWhich of the following does not have kinetic energy?
The drawn bow does not possess kinetic energy; option [D]. Kinetic energy refers to the energy an object possesses due to its motion. A fired bullet, flowing water, and a moving hammer all exhibit kinetic energy because they are in motion. However, a drawn bow, while potentially storing potential enRead more
The drawn bow does not possess kinetic energy; option [D]. Kinetic energy refers to the energy an object possesses due to its motion. A fired bullet, flowing water, and a moving hammer all exhibit kinetic energy because they are in motion. However, a drawn bow, while potentially storing potential energy due to its tension, lacks kinetic energy until it is released. At the point of release, the potential energy stored in the drawn bow is converted into kinetic energy as the arrow is propelled forward. Prior to release, the bow itself is not in motion and therefore does not possess kinetic energy. Instead, it stores potential energy, which is transformed into kinetic energy upon release, propelling the arrow forward with force derived from the tension stored in the bowstring.
See lessWhen the speed of a moving object doubles, its kinetic energy
When the speed of a moving object doubles, its kinetic energy quadruples; option [B]. This relationship is due to the fact that kinetic energy is directly proportional to the square of the velocity. According to the kinetic energy formula (K.E. = 1/2 m v^2) doubling the velocity results in the kinetRead more
When the speed of a moving object doubles, its kinetic energy quadruples; option [B]. This relationship is due to the fact that kinetic energy is directly proportional to the square of the velocity. According to the kinetic energy formula (K.E. = 1/2 m v^2) doubling the velocity results in the kinetic energy increasing by a factor of four. This principle is fundamental to understanding the relationship between velocity and kinetic energy in classical mechanics. Therefore, option B, quadruples, is the correct answer. It illustrates the significant impact that changes in velocity can have on the kinetic energy of a moving object. This relationship underscores the importance of velocity in determining the energy associated with the motion of an object, highlighting its role in various physical phenomena and calculations involving kinetic energy.
See lessMore energy is spent in climbing stairs, because
More energy is spent in climbing stairs because the person works against gravity; option [A]. When climbing stairs, the individual exerts force in the opposite direction to gravity's pull, lifting their body against it. This requires energy expenditure, as work is done to overcome gravity's resistanRead more
More energy is spent in climbing stairs because the person works against gravity; option [A]. When climbing stairs, the individual exerts force in the opposite direction to gravity’s pull, lifting their body against it. This requires energy expenditure, as work is done to overcome gravity’s resistance. In contrast, on flat ground, the person’s horizontal movement doesn’t involve significant gravitational opposition. The gravitational force acts perpendicular to the motion, so no work is done against it, unlike when ascending stairs where gravity opposes vertical motion. Therefore, option A, “the person works against gravity,” accurately explains the increased energy expenditure in stair climbing. This phenomenon aligns with the principle of conservation of energy, where the energy spent in lifting the body against gravity is transformed into potential energy. Consequently, climbing stairs demands more energy compared to walking on level ground due to the additional work required to overcome gravity’s resistance, highlighting the interplay between gravitational forces and human movement in energy expenditure.
See less