math july

. If the number 31200 is put in the form 3.12 ×10n, the value of n is
A. 1 B. 2 C. 2 D. 4 E. 5

1. The scientific notation 3.5 ×103 multiplied by 3 is
   A. 1.05 ×102 B.1.05×1010 C. 1.05×103 D.1.05×109 E. 1.05×104
2. The scientific notation 8.2×10-4 + 5.4×10-4=………
   A.1.35×10-5 B. 1.36×10-4 C.1.36×10-3 D.1.36×10-7 E.1.36×103
3. Which of the following is (are) true?
   A.log⁡〖(xy) 〗=log⁡x + log⁡y B. (log⁡x )^n = n log⁡x C. log_10⁡1=0
   . If we convert 135° to radian measure, we get
   A.3π/4 B.3π/2 C.π/4 D.π/2 E.(3+π)/2
4. 75° in radian measure is
   A.π/75 B.75/π C.5π/12 D.12π/5 E.π/30
   3.An arc PQ subtends an angle 60° at the centre O of radius 3 cm. The area of the sector POQ is
   A. 270 〖cm〗^2 B. 3/2 〖cm〗^2 C. 3π/2 〖cm〗^2 D. 3π 〖cm〗^2 E. 180 〖cm〗^2