State any two precautions taken to ensure accurate result on simple pendulum

Alinearly polarized electromagnetic wave has an average intensity of 196 w/m^2. this wave is directed towards two ideal polarizers (in real polarizers, transmission is also effected by reflection and absorption). polarizer a is oriented with its transmission axis at an angle of θ_1=20.8∘ with the incident electric field. polarizer b has its axis at an angle of θ_2=63.0∘ with the incident electric field. what is the average intensity of the wave after it passes through polarizer a? what is the average intensity of the wave after it passes through polarizer b? suppose that the two polarizers a and b are interchanged. what would the average intensity be after passing through both polarizers?

Which compound is held together by the electrostatic force between two ions? a. co2 b. cci4 c. h2s d. mgf2

Acar going 30 m/s to 70 m/s in 10 seconds calculate the acceleration of the car