S4 Phy Solutions To Exercise 01 Caltec S.4

SOLUTIONS TO S. 4 PHYICS EXERCISE 01 1. A converging lens acts as a magnifying glass when the object is ………………. A. at the principal focus B. between F and 2F C. beyond 2F D. be tween the lens and F 2. The force a body needs to move at a constant speed in circle is, A. centripetal force towards the centre B. centrifugal force towards the centre. C. centrifugal force away from the centre D. centripetal force away from the centre 3. An object is placed between two mirrors inclined at θ0 to each other. If N images are formed. Calculate the value of θ. A. 3600+𝑁+1 B. 𝟑𝟔𝟎𝟎 𝑵+𝟏 C. 𝑁+1 3600 D. 3600 𝑁−1 4. A body X moving at 6ms-1 hits a stationary body Y of the same mass and the two move together. What is their common velocity? A. 1ms-1 B. 2ms-1 C. 3ms-1 D. 6ms-1 5. The mass of a sample of radioactive iodine -131 is 800g. If the half -life of iodi ne -131 is 8 days, find the mass remaining undecayed after 32 days. A. 25g B. 50g C. 100g D. 200g 6. Mosquito larvae cling to water surfaces because A. it’s less dense than water. B. of surface tension of water C. of repulsion forces from water molecules D. of attraction from molecules above the water surface 7. A list of electrical appliances with their voltages and ratings is shown below: Appliance Power rating Voltage Car head lamp 48W 12V Electric drill 260W 250V Bedside lamp 50W 250V Electric iron 1500W 250V Which appliance has the highest resistance? A. Electric drill B. car head lamp C. Electric iron D. Bedside lamp 8. Moment of a couple is defined as the product of A. the sum of clockwise moments and anticlockwise moments …