(b) X-ray beam of wavelength 2.9 Å is diffracted from the plane of cubic crystal. The first order
diffraction is obtained at angle 35º. Calculate the
spacing between the planes. (Ans: 2.52 * 10-10m)

Read and key the following paragraph. 1"the final phase of franklin's public service is themost spectacular. 2after his return to america he waselected to the second continental congress and served withjefferson and john adams on the committee which drafted thedeclaration of independence. 3then, in 1776, he wasappointed one of the three commissioners to seek military andnaval assistance from france. 4for nearly ten years pariswas his center of operations, and, in large part because ofhis personal popularity, he secured the much-needed supportof france and spain and eventually negotiate thetreaty of paris (1783), by which england recognized americanindependence. 5when he returned to america in 1785 he wasold and ill, yet he found strength to serve as a delegate tothe constitutional convention, and to continue his work withmany humanitarian and scientific societies." type the key words for sentence's 2. 3. 4. 5.