What composition of lead-tin solder is the best choice for joining electronic components? why is this composition chosen?

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?