Astigmatism is an optical defect in which vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina. This may be due to an irregular or toric curvature of the cornea or lens. The two types of astigmatism are regular and irregular. Irregular astigmatism is often caused by a corneal scar or scattering in the crystalline lens, and cannot be corrected by standard spectacle lenses, but can be corrected by contact lenses. Regular astigmatism arising from either the cornea or crystalline lens can be corrected by a toric lens. This optical shape gives rise to regular astigmatism in the eye. Toric lens is somewhat similar in significance to cylindrical cells.

Correct Option: A

Astigmatism is an optical defect in which vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina. This may be due to an irregular or toric curvature of the cornea or lens. The two types of astigmatism are regular and irregular. Irregular astigmatism is often caused by a corneal scar or scattering in the crystalline lens, and cannot be corrected by standard spectacle lenses, but can be corrected by contact lenses. Regular astigmatism arising from either the cornea or crystalline lens can be corrected by a toric lens. This optical shape gives rise to regular astigmatism in the eye. Toric lens is somewhat similar in significance to cylindrical cells.

In electricity, a battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. A battery is a device that converts chemical energy directly to electrical energy. It consists of a number of voltaic cells; each voltaic cell consists of two half-cells connected in series by a conductive electrolyte containing anions and cations. One half-cell includes electrolyte and the electrode to which anions (negatively charged ions) migrate, i.e., the anode or negative electrode; the other half-cell includes electrolyte and the electrode to which cations (positively charged ions) migrate, i.e., the cathode or positive electrode. In the redox reaction that powers the battery, cations are reduced (electrons are added) at the cathode, while anions are oxidized (electrons are removed) at the anode.

Correct Option: C

In electricity, a battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. A battery is a device that converts chemical energy directly to electrical energy. It consists of a number of voltaic cells; each voltaic cell consists of two half-cells connected in series by a conductive electrolyte containing anions and cations. One half-cell includes electrolyte and the electrode to which anions (negatively charged ions) migrate, i.e., the anode or negative electrode; the other half-cell includes electrolyte and the electrode to which cations (positively charged ions) migrate, i.e., the cathode or positive electrode. In the redox reaction that powers the battery, cations are reduced (electrons are added) at the cathode, while anions are oxidized (electrons are removed) at the anode.

A hydrogen atom is very light. Most of the air on earth is made up of nitrogen, oxygen, and carbon dioxide. All of these elements are heavier than hydrogen, so the balloon is pushed upwards. Hydrogen weighs 0.08988 grams per liter. Nitrogen, which makes up 80% of the air we breathe, weighs 1.2506 grams per liter. Hydrogen filled balloons follow the same principle as we do when we float in the water; the law of buoyancy. If the water we displace weighs more than we do, we will float.

Correct Option: C

A hydrogen atom is very light. Most of the air on earth is made up of nitrogen, oxygen, and carbon dioxide. All of these elements are heavier than hydrogen, so the balloon is pushed upwards. Hydrogen weighs 0.08988 grams per liter. Nitrogen, which makes up 80% of the air we breathe, weighs 1.2506 grams per liter. Hydrogen filled balloons follow the same principle as we do when we float in the water; the law of buoyancy. If the water we displace weighs more than we do, we will float.

A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or “earth” through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution. Copper and its alloys are the most common materials used in lightning protection. Copper does not attract lightning, but it effectively and rapidly facilitates the transmission of lightning energy to the ground because of its excellent electrical conductivity and corrosion resistance characteristics. Also, it bends easily compared to other conductor materials.

Correct Option: C

A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or “earth” through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution. Copper and its alloys are the most common materials used in lightning protection. Copper does not attract lightning, but it effectively and rapidly facilitates the transmission of lightning energy to the ground because of its excellent electrical conductivity and corrosion resistance characteristics. Also, it bends easily compared to other conductor materials.

Sir Isaac Newton brought out his monograph, titled ‘Philosophiæ Naturalis Principia Mathematica,’ in 1687. In this work, Newton described universal gravitation and the three laws of motion, which dominated the scientific view of the physical universe for the next three centuries. Newton showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws, by demonstrating the consistency between Kepler’s laws of planetary motion and his theory of gravitation, thus removing the last doubts about helio-centrism and advancing the Scientific Revolution. Newton’s law of universal gravitation states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Correct Option: A

Sir Isaac Newton brought out his monograph, titled ‘Philosophiæ Naturalis Principia Mathematica,’ in 1687. In this work, Newton described universal gravitation and the three laws of motion, which dominated the scientific view of the physical universe for the next three centuries. Newton showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws, by demonstrating the consistency between Kepler’s laws of planetary motion and his theory of gravitation, thus removing the last doubts about helio-centrism and advancing the Scientific Revolution. Newton’s law of universal gravitation states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.