1.What is the ‘stroboscopic effect’? Describe why it may be dangerous and explain


how it may be overcome. 2. A hospital corridor is lit by twelve 100 W GLS lamps. As an economy measure, the GLS lamps are to be replaced with SL18 integral compact-fluorescent lamps, each of which consumes 18Wand provides a similar lumen output to the 100W GLS types. If the GLS lamps have an expected life of 1000 hours at a cost of 34p each and SL18s are rated 5000 hours and cost £5.25 each, calculate the cost saving over a burning period of 10 000 hours. Ignore the savings in labour costs for lamp changing, and assume that the energy cost over the period will be 5.2p/kWh.