Category: Physics

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 […]

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 tan90 value? The value of tan 30 is 1/√3. What is the value of Cosec 0? The value of cosec at 0° is the reciprocal of sin at 0°. How do you find the value of Cosec? Find the value of cosec(−1410∘) Therefore write 1410∘ as (4×2π−30∘) and proceed. Complete step-by-step answer: We […]

What is U value of insulation? A U-value is a sum of the thermal resistances of the layers that make up an entire building element – for example, a roof, wall or floor. It also includes adjustments for any fixings or air gaps. Is it better to have a higher or lower thermal conductivity? A […]

Is it better to be upstairs or downstairs in an earthquake? In an earthquake, the area immediately outside a building is the most dangerous place to be. The taller the building, the wider the danger zone. A basic rule of thumb is if you are inside, stay inside and if you are outside, stay outside. […]

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. […]

What time of day are shadows the longest? Shadows are longest in the early morning and late afternoon/early evening when the sun appears low in the sky. As the Earth rotates on its axis, the sun hits each location in the morning at an angle. This becomes more vertical as the sun appears to pass […]

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 […]

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 […]

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, […]