Which of the following is a more accurate measuring instrument?

The photograph of a house occupies an area of 1.75 cm² on a 35 mm slide.The slide is projected on to a screen,and the area of the house on the screen is 1.55 m².What is the linear magnification of the projector,screen arrangement?

The angle subtended by a satellite by the two directions of observation is 2.552 x 10^-2 rad.If the diameter of earth is  1.276 x 10⁷m. What is the distance of the satellite from the earth?

The number of electrons that would weigh 9.11 kg is

Candela is the unit of 

In a SONAR system, the duration between sending of a search wave and receiving back of the reflected wave from an enemy submarine is 77s.If speed of sound in water is 1450 m/s,find the distance of the energy submarine.

The number of significant figures in 200.01 are

Parallax angle of a heavenly body measured from two points diametrically opposite on the equator of the earth is 1.0 minute.If the radius of the earth is 6400 km,find the distance of the heavenly body from the earth.

A   LASER  beam at moon returns after 2.56 s from moon.What is the radius of the orbit of moon (lunar orbit) around the earth?

The number of significant figures is 271.00 is