12.
									
										What does θ signifies in Brags equation: 2d Sin θ=nλ 
									
								
															
														
																									
										A:
											 Angle between incident x-ray and diffracted x-ray
									
																										
										B:
											 Angle between incident x-ray and plane of crystal 
									
																										
										C:
											Angle between incident x-ray and protein molecule 
									
																										
										D:
											 Angle between incident x-ray and x-ray grid
									
																								 
							
																
									The answer is:
										B
									
								
														
							
								
								
							
							
							
								