Category: Physics

How is DNA used to identify individuals? DNA fingerprinting is a chemical test that shows the genetic makeup of a person or other living things. It’s used as evidence in courts, to identify bodies, track down blood relatives, and to look for cures for disease. What are the steps of gel electrophoresis? There are several […]

What is a disadvantage of hydrogen fuel cells? There are disadvantages to using hydrogen-oxygen fuel cells in cars. These include: hydrogen is in the gas state at room temperature and pressure, so it is difficult to store in the car. fuel cells and electric motors are less durable than petrol engines and diesel engines, so […]

How do I find the volume of my washer? The formula for the volume of a washer requires both an inner radius r1 and outer radius r2. We’ll need to know the volume formula for a single washer. V = π (r22 – r12) h = π (f(x)2 – g(x)2) dx. As before, the exact […]

Why is NO2 not a greenhouse gas? Neither nitric oxide nor nitrogen dioxide are greenhouse gases, although they are important in the process of creation of tropospheric ozone which is a greenhouse gas. Because of this, there is general agreement that the atmospheric sources and sinks of nitrous oxide are difficult to bring into balance. […]

How a ring main is wired? The mains supply The power sockets in a house are connected by means of a ring circuit. In a ring circuit the live, neutral and earth wires form a loop of cable going from the consumer unit to all of the sockets in turn and then back to the […]

Which three of the following are examples of feedback mechanisms which help maintain homeostasis? Answer: The correct answer is- C. Insulin secretion in response to high blood sugar. D. F. Homeostasis can be described as a tendency of living organisms to maintain a state of stable internal environment. Thus, option C), D), and F) are […]

Does salt increase water density? Density is the mass of a material per unit volume. Adding salt to the water increases the density of the solution because the salt increases the mass without changing the volume very much. When enough salt is added to the water, the saltwater solution’s density becomes higher than the egg’s, […]

What is the source of energy for the life in deep sea ocean trenches where sunlight does not reach? Answer: Instead of sunlight, vent life relies on hydrogen sulfide – more commonly known as rotten egg gas and toxic to most land-based life. In a process called chemosynthesis, specialized bacteria create energy from the hydrogen […]

Can a tuning fork go out of tune? No, you can’t whack a fork too hard and make it ring out of tune! It will have been like that from the factory. You can re-tune a fork that is flat by grinding of some material from the ends of both forks. grind it a tiny […]

What are general fire precautions? The term ‘general fire precautions’ (GFPs) is used to mean the measures in places of work to reduce the risk of fire and its spread on the premises, and include: providing arrangements for action to be taken in the event of a fire on the premises, including: the instruction and […]