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What keeps an electron moving in a circle around the nucleus of an atom? a gravitational force away from the nucleus, a gravitational force towards the nucleus, an electro
Which statement about the pressure in a column of liquid is correct? It acts only vertically downwards., It increases if the column width increases., It increases with
An airtight container holds a fixed quantity of gas. Its pressure and volume are measured on four occasions when the temperature is 20 °C. The results are shown in the table.Which set of readings is incorrect? pressure / kPa 120 volume / cm3 36, pressure / kPa 100 volume / cm3 48, pressure / kPa
In a vacuum flask, which methods of heat transfer are prevented by the vacuum? conduction only, convection only, conduction and convection only, conduction, convection, and rad
Ice is taken from a freezer and left in a room. The ice melts and eventually the water reaches room temperature. Which energy transfers take place? from ice to room from water to room, from ice to room from room to water, from room to i
Some air is trapped inside a small balloon. The average kinetic energy of the air molecules in the balloon is increased. What remains the same? the density of the air in the balloon, the mass of the air in the balloon, the temperature of the
Which colour, red or blue, has the higher frequency and which has the longer wavelength? higher frequency blue longer wavelength blue, higher frequency blue longer wavelength
A perspex rod can be charged positively by rubbing it with a woollen cloth. How does the rod gain its charge? The rod gains electrons., The rod gains protons., The rod loses electrons., The rod loses protons.
Which travels in a straight line across a magnetic field? alpha-particle, electron, gamma-ray, proton
In the treatment of brain cancer, a patient’s head is enclosed in a helmet containing a number of radioactive sources. The radiation from each source is directed towards the cancer.Which nuclide is the most suitable for these sources? nuclide caesium-137 radiation gamma half-life 30 years, nuclide sodium-24 radiation b
A nucleus of the element cobalt may be represented by the symbol Co 59/27 . What is the structure of this nucleus? number of protons 27 number of neutrons 32, number of protons 27 number of neutrons 59,
How is the motion of a body affected by balanced and unbalanced forces acting on it? balanced forces velocity changes unbalanced forces velocity changes, balanced forces elocity
Where is energy released by the fusion of hydrogen atoms to form helium? in a nuclear power station, in a radioactive isotope, in the core of the Earth, in the core of the
A crane lifts a weight of 1000 N through a vertical height of 30 m. It uses 60 000 J of energy. What is the efficiency of the crane? 0.2, 0.3, 0.4, 0.5
A rock climber of weight 600 N climbs up a rock face of vertical height 300 m in 3600 s. What is the average power she generates against gravity during this time? 0.020 W, 50 W , 1800 W, 7200 W
Using an electric kettle, 100 g of water at 100 °C is converted into steam at 100 °C in 300 seconds. The specific latent heat of steam is 2250 J / g. What is the average electrical power used? 2250 /300 x 100 W , 100 × 2250 / 100 W, 300 × 2250 / 100 W, 100 × 300 × 2250 W
The option shows the increase in length of four metals when heated through the same temperature rise. Each metal initially has the same length. metal aluminium increase in length / m 0.000030, metal copper increase in length
When ice melts to become water, which force must be overcome? the attraction between electrons and the nucleus, the attraction between the atoms in a molecule, t
Which factors increase the rate of evaporation of a liquid? increasing its temperature yes increasing its surface area yes increasing its depth
In a short-sighted eye, rays from distant objects are not focused on the retina. Where are these rays focused and what type of lens is needed to correct the problem? behind the retina converging lens, behind the retina diverging lens, in front of the retina converg
Delicate instruments are often placed in a ‘box’ to protect them from stray magnetic fields.What is the material used for the box and why is it chosen? Aluminium is used because it is a non-magnetic material., Copper is used because it has a low elect
A piece of polythene is rubbed with a cloth duster. The polythene becomes negatively charged and the cloth becomes positively charged.What happens to the polythene and to the cloth to cause this? polythene gains electrons cloth gains protons, polythene gains electrons cloth loses
The current in an electric heater is 10 A. It is switched on for five minutes. How much charge flows through the heater? 0.5 C , 2 C , 50 C, 3000 C
An electric heater is rated at 3 kW. Electrical energy costs 20 cents per kW h. What is the cost of using the heater for five hours? 12 cents , 60 cents , 100 cents, 300 cents
What is the purpose of a circuit breaker in an electric circuit? to change alternating current into direct current, to keep the current constant, to prevent the cur
The e.m.f. induced in a conductor moving at right-angles to a magnetic field does not depend upon the length of the conductor., the resistance of the conductor., the speed of the conductor., the st
What occurs in the decay of a radioactive nucleus? The nucleus absorbs another nucleus., The nucleus absorbs at least one form of radiation., The nucle
The radioactive nucleus 87 / 37 Rb decays with the emission of a beta-particle. How many protons and neutrons are left in the nucleus? protons 37 neutrons 49, protons 37 neutrons 50, protons 38 neutrons 49, protons 38 neutrons