1. Central axis depth dose for lower energy x-ray is maximum at - (i) 0.5cm depth from the surface (ii) 5cm from surface (iii) surface of the phantom (iv) none of these 2. The most... 1. Central axis depth dose for lower energy x-ray is maximum at - (i) 0.5cm depth from the surface (ii) 5cm from surface (iii) surface of the phantom (iv) none of these 2. The most useful treatment depth of electron is given by depth of - (i) 90% (ii) 50% (iii) 80% (iv) 70% 3. Electron beam can be considered as - (i) mono-energetic (ii) hetero-energetic (iii) low energetic (iv) none of these 4. The range of 9MeV electron beam in water is approximately - (i) 4.5 cm (ii) 10cm (iii) 5cm (iv) none of these 5. For ortho-voltage x-ray, the reference depth dose is at - (i) d=0 (ii) d=0.5cm (iii) 5cm (iv) 10cm 6. Which one is the most predominant mode of interaction for megavoltage photon beam in the clinical range? (i) Photo-electric effect (ii) Compton effect (iii) Pair production (iv) Auger effect 7. Which tissues are most sensitive to radiation? (i) Gonads (ii) Lungs (iii) Skin (iv) Breast 8. Curie is the unit of - (i) exposure (ii) dose (iii) equivalent dose (iv) activity 9. S.I unit of KERMA - (i) Sievert (ii) C/kg (iii) Gray (iv) rem 10. TAR is independent of - (i) beam energy (ii) field size (iii) depth (iv) SSD 11. Iso-dose curves are lines passing through the points of - (i) equal dose (ii) equal depth (iii) equal field size (iv) different dose 12. Tilt of iso-dose curves depends on - (i) size of the wedge filter (ii) slope of the wedge filter (iii) composition of the wedge filter (iv) distance of the wedge filter from skin Read more