Final math (s1)

Question 1

Covert 5/6 to a decimal:

Answer 1

.83333

Question 2

Covert 8/3 to a decimal:

Answer 2

2.6777

Question 3

X/9 =5/4

Solve for x=

Question 4

Area of an X-ray field that measures 10 cm by 12 cm

Answer 4

120 cm

Question 5

A radiograph is produced at a distance of 40” and results in an exposure of 10 mGy. If the SID is increased to 60”, what is the new exposure in mGy?

Answer 5

mGy/ (x) (New)^2/(old)^2

10 / x 60”^2 / 40”^2= 3600/1600

10 mGy x the old 1600= 16,000 / (new) 3600= 4.44444

Question 6

A radiograph is produced at a distance of 50” and results in an exposure of 5mGy. If the SID is decreased to 30”, what is the new exposure in mGy?

Question 7

V=30 m/s f=6 ¥=?

Question 8

V=20 m/s f=? ¥=2m

Question 9

V=? I=3 R=80

Answer 9

V= I x R
V= 3 x 80= 240 volts

Question 10

mA 500 220 volts
The secondary coil of a transformer has 10,000 turns and the primary coil has 100 turns.

Answer 10

Step up transformer
100:1
Voltage is going to increase so:
220v x 100= 22,000 volts
100/ 500= .2 mA?

Question 11

500 mA 220 V
The secondary coil of a transformer has 500 turns and the primary has 10,000 turns.

Answer 11

Step down transformer
Voltage decrease, amperage increase
220v / 20 = 6 volts
20 x 500 mA = 10000 mA

Question 12

Heat units
70 kvp .1 sec 300 mA

Answer 12

1.4 (constant) x kvp x mAs x s
2940 HU

Question 13

Heat units
80 kVp, .2 sec, 400 mA

Answer 13

1.4 x 80 kvp x 400 mA x .2 seconds
8960?